Militia following ratification.

During the first two decades following the ratification of the Second Amendment, public opposition to standing armies, among Anti-Federalists and Federalists alike, persisted and manifested itself locally as a general reluctance to create a professional armed police force, instead relying on county sheriffs, constables and night watchmen to enforce local ordinances. Though sometimes compensated, often these positions were unpaid – held as a matter of civic duty. In these early decades, law enforcement officers were rarely armed with firearms, using billy clubs as their sole defensive weapons. In serious emergencies, a posse comitatus, militia company, or group of vigilantes assumed law enforcement duties; these individuals were more likely than the local sheriff to be armed with firearms.

On May 8, 1792, Congress passed "n act more effectually to provide for the National Defense, by establishing an Uniform Militia throughout the United States" requiring:

each and every free able-bodied white male citizen of the respective States, resident therein, who is or shall be of age of eighteen years, and under the age of forty-five years (except as is hereinafter excepted) shall severally and respectively be enrolled in the militia ...  every citizen so enrolled and notified, shall, within six months thereafter, provide himself with a good musket or firelock, a sufficient bayonet and belt, two spare flints, and a knapsack, a pouch with a box therein to contain not less than twenty-four cartridges, suited to the bore of his musket or firelock, each cartridge to contain a proper quantity of powder and ball: or with a good rifle, knapsack, shot-pouch and powder-horn, twenty balls suited to the bore of his rifle, and a quarter of a pound of powder; and shall appear, so armed, accoutred and provided, when called out to exercise, or into service, except, that when called out on company days to exercise only, he may appear without a knapsack.

The act also gave specific instructions to domestic weapon manufacturers "that from and after five years from the passing of this act, muskets for arming the militia as herein required, shall be of bores sufficient for balls of the eighteenth part of a pound." In practice, private acquisition and maintenance of rifles and muskets meeting specifications and readily available for militia duty proved problematic; estimates of compliance ranged from 10 to 65 percent. Compliance with the enrollment provisions was also poor. In addition to the exemptions granted by the law for custom-house officers and their clerks, post-officers and stage drivers employed in the care and conveyance of U.S. mail, ferrymen, export inspectors, pilots, merchant mariners and those deployed at sea in active service; state legislatures granted numerous exemptions under Section 2 of the Act, including exemptions for: clergy, conscientious objectors, teachers, students, and jurors. Though a number of able-bodied white men remained available for service, many simply did not show up for militia duty. Penalties for failure to appear were enforced sporadically and selectively. None is mentioned in the legislation.

Drafting and adoption of the Constitution.

In March 1785, delegates from Virginia and Maryland assembled at the Mount Vernon Conference to fashion a remedy to the inefficiencies of the Articles of Confederation. The following year, at a meeting in Annapolis, Maryland, 12 delegates from five states (New Jersey, New York, Pennsylvania, Delaware, and Virginia) met and drew up a list of problems with the current government model. At its conclusion, the delegates scheduled a follow-up meeting in Philadelphia, Pennsylvania for May 1787 to present solutions to these problems, such as the absence of:

interstate arbitration processes to handle quarrels between states;

sufficiently trained and armed intrastate security forces to suppress insurrection;

 a national militia to repel foreign invaders.

It quickly became apparent that the solution to all three of these problems required shifting control of the states' militias to the federal Congress and giving it the power to raise a standing army. Article 1, Section 8 of the Constitution codified these changes by allowing the Congress to provide for the common defense and general welfare of the United States by doing the following:

raise and support armies, but no appropriation of money to that use shall be for a longer term than two years;

provide and maintain a navy;

make rules for the government and regulation of the land and naval forces;

provide for calling forth the militia to execute the laws of the union, suppress insurrections and repel invasions;

provide for organizing, arming, and disciplining the militia, and for governing such part of them as may be employed in the service of the United States, reserving to the states respectively, the appointment of the officers, and the authority of training the militia according to the discipline prescribed by Congress.

Some representatives mistrusted proposals to enlarge federal powers, because they were concerned about the inherent risks of centralizing power. Federalists, including James Madison, initially argued that a bill of rights was unnecessary, sufficiently confident that the federal government could never raise a standing army powerful enough to overcome a militia. Federalist Noah Webster argued that an armed populace would have no trouble resisting the potential threat to liberty of a standing army. Anti-federalists, on the other hand, advocated amending the Constitution with clearly defined and enumerated rights providing more explicit constraints on the new government. Many Anti-federalists feared the new federal government would choose to disarm state militias. Federalists countered that in listing only certain rights, unlisted rights might lose protection. The Federalists realized there was insufficient support to ratify the Constitution without a bill of rights and so they promised to support amending the Constitution to add a bill of rights following the Constitution's adoption. This compromise persuaded enough Anti-federalists to vote for the Constitution, allowing for ratification. The Constitution was declared ratified on June 21, 1788, when nine of the original thirteen states had ratified it. The remaining four states later followed suit, although the last two states, North Carolina and Rhode Island, ratified only after Congress had passed the Bill of Rights and sent it to the states for ratification. James Madison drafted what ultimately became the Bill of Rights, which was proposed by the first Congress on June 8, 1789, and was adopted on December 15, 1791.

Preserving slave patrols.

In the slave states, the militia was available for military operations, but its biggest function was to police the slaves.

Settlers in Colonial America viewed the right to arms and/or the right to bear arms and/or state militias as important for one or more of these purposes (in no particular order):

enabling the people to organize a militia system

participating in law enforcement

safeguarding against tyrannical governments

repelling invasion

suppressing insurrection, allegedly including slave revolts, though some scholars say the claim of a specific intent to protect the ability to put down slave revolts is not supported by the historical record

facilitating a natural right of self-defense

Which of these considerations were thought of as most important and ultimately found expression in the Second Amendment is disputed. Some of these purposes were explicitly mentioned in early state constitutions; for example, the Pennsylvania Constitution of 1776 asserted that, "the people have a right to bear arms for the defense of themselves and the state."

During the 1760s pre-revolutionary period, the established colonial militia was composed of colonists, including many who were loyal to British rule. As defiance and opposition to British rule developed, a distrust of these Loyalists in the militia became widespread among the colonists known as Patriots, who favored independence from British rule. As a result, some Patriots created their own militias that excluded the Loyalists and then sought to stock independent armories for their militias. In response to this arms build-up, the British parliament established an embargo of firearms, parts and ammunition against the American colonies. King George III also began disarming individuals who were in the most rebellious areas in the 1760s and 1770s.

British and Loyalist efforts to disarm the colonial Patriot militia armories in the early phases of the American Revolution resulted in the Patriot colonists protesting by citing the Declaration of Rights, Blackstone's summary of the Declaration of Rights, their own militia laws and common law rights to self-defense. While British policy in the early phases of the Revolution clearly aimed to prevent coordinated action by the Patriot militia, some have argued that there is no evidence that the British sought to restrict the traditional common law right of self-defense. Patrick J. Charles disputes these claims citing similar disarming by the patriots and challenging those scholars' interpretation of Blackstone.

The right of the colonists to arms and rebellion against oppression was asserted, for example, in a pre-revolutionary newspaper editorial in 1769 objecting to the Crown suppression of colonial opposition to the Townshend Acts:

Instances of the licentious and outrageous behavior of the military conservators of the peace still multiply upon us, some of which are of such nature, and have been carried to such lengths, as must serve fully to evince that a late vote of this town, calling upon its inhabitants to provide themselves with arms for their defense, was a measure as prudent as it was legal: such violences are always to be apprehended from military troops, when quartered in the body of a populous city; but more especially so, when they are led to believe that they are become necessary to awe a spirit of rebellion, injuriously said to be existing therein. It is a natural right which the people have reserved to themselves, confirmed by the Bill of Rights, to keep arms for their own defense; and as Mr. Blackstone observes, it is to be made use of when the sanctions of society and law are found insufficient to restrain the violence of oppression.

The Second Amendment to the United States Constitution protects the right to keep and bear arms. It was ratified on December 15, 1791, along with nine other articles of the Bill of Rights. In District of Columbia v Heller (2008), the Supreme Court affirmed for the first time that the right belongs to individuals, for self-defense in the home, while also including, as dicta, that the right is not unlimited and does not preclude the existence of certain long-standing prohibitions such as those forbidding "the possession of firearms by felons and the mentally ill" or restrictions on "the carrying of dangerous and unusual weapons". In McDonald v City of Chicago (2010) the Supreme Court ruled that state and local governments are limited to the same extent as the federal government from infringing upon this right.

The Second Amendment was based partially on the right to keep and bear arms in English common law and was influenced by the English Bill of Rights of 1689. Sir William Blackstone described this right as an auxiliary right, supporting the natural rights of self-defense and resistance to oppression, and the civic duty to act in concert in defense of the state. Any labels of rights as auxiliary must be viewed in the context of the inherent purpose of a Bill of Rights, which is to empower a group with the ability to achieve a mutually desired outcome, and not to necessarily enumerate or rank the importance of rights. Thus all rights enumerated in a Constitution are thus auxiliary in the eyes of Sir William Blackstone because all rights are only as good as the extent they are exercised in fact. While both James Monroe and John Adams supported the Constitution being ratified, its most influential framer was James Madison. In Federalist No. 46, Madison wrote how a federal army could be kept in check by state militias, "a standing army ... would be opposed to a militia." He argued that state militias "would be able to repel the danger" of a federal army, "It may well be doubted whether a militia thus circumstanced could ever be conquered by such a proportion of regular troops." He contrasted the federal government of the United States to the European kingdoms, which he described as "afraid to trust the people with arms", and assured that "the existence of subordinate governments ... forms a barrier against the enterprises of ambition".

By January 1788, Delaware, Pennsylvania, New Jersey, Georgia and Connecticut ratified the Constitution without insisting upon amendments. Several amendments were proposed, but were not adopted at the time the Constitution was ratified. For example, the Pennsylvania convention debated fifteen amendments, one of which concerned the right of the people to be armed, another with the militia. The Massachusetts convention also ratified the Constitution with an attached list of proposed amendments. In the end, the ratification convention was so evenly divided between those for and against the Constitution that the federalists agreed to the Bill of Rights to assure ratification. In United States v Cruikshank (1876), the Supreme Court ruled that, "The right to bear arms is not granted by the Constitution; neither is it in any manner dependent upon that instrument for its existence. The Second Amendments means no more than that it shall not be infringed by Congress, and has no other effect than to restrict the powers of the National Government." In United States v Miller (1939), the Supreme Court ruled that the Second Amendment did not protect weapon types not having a "reasonable relationship to the preservation or efficiency of a well regulated militia".

Petition and assembly.

The Petition Clause protects the right "to petition the government for a redress of grievances". The right expanded over the years: "It is no longer confined to demands for 'a redress of grievances', in any accurate meaning of these words, but comprehends demands for an exercise by the government of its powers in furtherance of the interest and prosperity of the petitioners and of their views on politically contentious matters." The right to petition the government for a redress of grievances therefore includes the right to communicate with government officials, lobbying government officials and petitioning the courts by filing lawsuits with a legal basis. The Petition Clause first came to prominence in the 1830s, when Congress established the gag rule barring anti-slavery petitions from being heard; the rule was overturned by Congress several years later. Petitions against the Espionage Act of 1917 resulted in imprisonment. The Supreme Court did not rule on either issue.

In California Motor Transport Co. v Trucking Unlimited (1972), the Supreme Court said the right to petition encompasses "the approach of citizens or groups of them to administrative agencies (which are both creatures of the legislature, and arms of the executive) and to courts, the third branch of Government. Certainly the right to petition extends to all departments of the Government. The right of access to the courts is indeed but one aspect of the right of petition." Today, thus, this right encompasses petitions to all three branches of the federal government—the Congress, the executive and the judiciary—and has been extended to the states through incorporation. According to the Supreme Court, "redress of grievances" is to be construed broadly: it includes not solely appeals by the public to the government for the redressing of a grievance in the traditional sense, but also, petitions on behalf of private interests seeking personal gain. The right protects not only demands for "a redress of grievances" but also demands for government action. The petition clause includes, according to the Supreme Court, the opportunity to institute non-frivolous lawsuits and mobilize popular support to change existing laws in a peaceful manner.

In Borough of Duryea v Guarnieri (2011), the Supreme Court stated regarding the Free Speech Clause and the Petition Clause:

It is not necessary to say that the two Clauses are identical in their mandate or their purpose and effect to acknowledge that the rights of speech and petition share substantial common ground ... Both speech and petition are integral to the democratic process, although not necessarily in the same way. The right to petition allows citizens to express their ideas, hopes, and concerns to their government and their elected representatives, whereas the right to speak fosters the public exchange of ideas that is integral to deliberative democracy as well as to the whole realm of ideas and human affairs. Beyond the political sphere, both speech and petition advance personal expression, although the right to petition is generally concerned with expression directed to the government seeking redress of a grievance.

Obscenity.

According to the U.S. Supreme Court, the First Amendment's protection of free speech does not apply to obscene speech. Therefore, both the federal government and the states have tried to prohibit or otherwise restrict obscene speech, in particular the form that is now called pornography. As of 2019, pornography, except for child pornography, is in practice free of governmental restrictions in the United States, though pornography about "extreme" sexual practices is occasionally prosecuted. The change in the twentieth century, from total prohibition in 1900 to near-total tolerance in 2000, reflects a series of court cases involving the definition of obscenity. The U.S. Supreme Court has found that most pornography is not obscene, a result of changing definitions of both obscenity and pornography. The legal tolerance also reflects changed social attitudes: one reason there are so few prosecutions for pornography is that juries will not convict.

In Rosen v United States (1896), the Supreme Court adopted the same obscenity standard as had been articulated in a famous British case, Regina v Hicklin (1868). The Hicklin test defined material as obscene if it tended "to deprave or corrupt those whose minds are open to such immoral influences, and into whose hands a publication of this sort may fall". In the early twentieth century, literary works including An American Tragedy (Theodore Dreiser, 1925) and Lady Chatterley's Lover (D.H. Lawrence, 1928) were banned for obscenity. In the federal district court case United States v One Book Called Ulysses (1933), Judge John M. Woolsey established a new standard to evaluate James Joyce's novel Ulysses (1922), stating that works must be considered in their entirety, rather than declared obscene on the basis of an individual part of the work.

The Supreme Court ruled in Roth v United States (1957) that the First Amendment did not protect obscenity. It also ruled that the Hicklin test was inappropriate; instead, the Roth test for obscenity was "whether to the average person, applying contemporary community standards, the dominant theme of the material, taken as a whole, appeals to the prurient interest". This definition proved hard to apply, however, and in the following decade, members of the Court often reviewed films individually in a court building screening room to determine if they should be considered obscene. Justice Potter Stewart, in Jacobellis v Ohio (1964), famously said that, although he could not precisely define pornography, "I know it when I see it".

The Roth test was expanded when the Court decided Miller v California (1973). Under the Miller test, a work is obscene if:

(a) ... 'the average person, applying contemporary community standards' would find the work, as a whole, appeals to the prurient interest ... (b) ... the work depicts or describes, in a patently offensive way, sexual conduct specifically defined by the applicable state law, and (c) ... the work, taken as a whole, lacks serious literary, artistic, political, or scientific value.

Note that "community" standards—not national standards—are applied whether the material appeals to the prurient interest, leaving the question of obscenity to local authorities. Child pornography is not subject to the Miller test, as the Supreme Court decided in New York v Ferber (1982) and Osborne v Ohio (1990), ruling that the government's interest in protecting children from abuse was paramount.

Anonymous speech

In Talley v California (1960), the Court struck down a Los Angeles city ordinance that made it a crime to distribute anonymous pamphlets. Justice Hugo Black wrote in the majority opinion: "There can be no doubt that such an identification requirement would tend to restrict freedom to distribute information and thereby freedom of expression. ... Anonymous pamphlets, leaflets, brochures and even books have played an important role in the progress of mankind." In McIntyre v Ohio Elections Commission (1995), the Court struck down an Ohio statute that made it a crime to distribute anonymous campaign literature. However, in Meese v Keene (1987), the Court upheld the Foreign Agents Registration Act of 1938, under which several Canadian films were defined as "political propaganda", requiring their sponsors to be identified.

Campaign finance.

In Buckley v Valeo (1976), the Supreme Court reviewed the Federal Election Campaign Act of 1971 and related laws, which restricted the monetary contributions that may be made to political campaigns and expenditure by candidates. The Court affirmed the constitutionality of limits on campaign contributions, saying they "serve the basic governmental interest in safeguarding the integrity of the electoral process without directly impinging upon the rights of individual citizens and candidates to engage in political debate and discussion." However, the Court overturned the spending limits, which it found imposed "substantial restraints on the quantity of political speech".

The court again scrutinized campaign finance regulation in McConnell v Federal Election Commission (2003). The case centered on the Bipartisan Campaign Reform Act of 2002 (BCRA), a federal law that imposed new restrictions on campaign financing. The Supreme Court upheld provisions which barred the raising of soft money by national parties and the use of soft money by private organizations to fund certain advertisements related to elections. However, the Court struck down the "choice of expenditure" rule, which required that parties could either make coordinated expenditures for all its candidates, or permit candidates to spend independently, but not both, which the Court agreed "placed an unconstitutional burden on the parties' right to make unlimited independent expenditures". The Court also ruled that the provision preventing minors from making political contributions was unconstitutional, relying on Tinker v Des Moines Independent Community School District.

Freedom of speech and of the press.

The First Amendment broadly protects the rights of free speech and free press. Free speech means the free and public expression of opinions without censorship, interference and restraint by the government. The term "freedom of speech" embedded in the First Amendment encompasses the decision what to say as well as what not to say. Free press means the right of individuals to express themselves through publication and dissemination of information, ideas and opinions without interference, constraint or prosecution by the government.

The Supreme Court of the United States characterized the rights of free speech and free press as fundamental personal rights and liberties and noted that the exercise of these rights lies at the foundation of free government by free men. In Bond v Floyd (1966), a case involving the Constitutional shield around the speech of elected officials, the Supreme Court declared that the First Amendment central commitment is that, in the words of New York Times Co. v Sullivan (1964), "debate on public issues should be uninhibited, robust, and wide-open." The Court further explained that just as erroneous statements must be protected to give freedom of expression the breathing space it needs to survive, so statements criticizing public policy and the implementation of it must be similarly protected. The Supreme Court in Chicago Police Dept. v Mosley (1972) said:

"But, above all else, the First Amendment means that the government has no power to restrict expression because of its message, its ideas, its subject matter, or its content.  To permit the continued building of our politics and culture, and to assure self-fulfillment for each individual, our people are guaranteed the right to express any thought, free from government censorship. The essence of this forbidden censorship is content control. Any restriction on expressive activity because of its content would completely undercut the "profound national commitment to the principle that debate on public issues should be uninhibited, robust, and wide-open.""

The level of protections with respect to free speech and free press given by the First Amendment is not limitless. As stated in his concurrence in Chicago Police Dept. v Mosley (1972), Chief Justice Warren E. Burger said:

"Numerous holdings of this Court attest to the fact that the First Amendment does not literally mean that we "are guaranteed the right to express any thought, free from government censorship." This statement is subject to some qualifications, as for example those of Roth v United States (1957); Chaplinsky v New Hampshire (1942). Refer also to New York Times Company v Sullivan (1964)."

Attached to the rights of free speech and free press as the core rights to utter and to print are several peripheral rights that make these core rights more secure. The peripheral rights encompass not only freedom of association, including privacy in one's associations, but also, in the words of Griswold v Connecticut (1965), "the freedom of the entire university community", for example, the right to distribute, the right to receive, and the right to read, as well as freedom of inquiry, freedom of thought, and freedom to teach. The United States Constitution protects, according to the Supreme Court in Stanley v Georgia (1969), the right to receive information and ideas, regardless of their social worth, and to be generally free from governmental intrusions into one's privacy and control of one's thoughts. As stated by the Court in Stanley: "If the First Amendment means anything, it means that a State has no business telling a man, sitting alone in his own house, what books he may read or what films he may watch. Our whole constitutional heritage rebels at the thought of giving the government the power to control men's minds."

Accommodationists

Accommodationists, in contrast, argue along with Justice William O Douglas that "we are a religious people whose institutions presuppose a Supreme Being." Furthermore, as observed by Chief Justice Warren E Burger in Walz v Tax Commission of the City of New York (1970) with respect to the separation of church and state: "No perfect or absolute separation is really possible; the very existence of the Religion Clauses is an involvement of sorts—one that seeks to mark boundaries to avoid excessive entanglement." He also coined the term "benevolent neutrality" as a combination of neutrality and accommodationism in Walz to characterize a way to ensure that there is no conflict between the Establishment Clause and the Free Exercise Clause. Burger's successor, William Rehnquist, called for the abandonment of the "wall of separation between church and State" metaphor in Wallace v Jaffree (1985), because he believed this metaphor was based on bad history and proved itself useless as a guide to judging.

David Shultz has said that accommodationists claim the Lemon test should be applied selectively. As such, for many conservatives, the Establishment Clause solely prevents the establishment of a state church, not public acknowledgements of God nor 'developing policies that encourage general religious beliefs that do not favor a particular sect and are consistent with the secular government's goals'. In Lynch v Donnelly (1984), the Supreme Court observed that the "concept of a "wall" of separation between church and state is a useful metaphor, but is not an accurate description of the practical aspects of the relationship that in fact exists. The Constitution does not require complete separation of church and state; it affirmatively mandates accommodation, not merely tolerance, of all religions, and forbids hostility toward any."

Free exercise of religion.

The acknowledgement of religious freedom as the first right protected in the Bill of Rights points toward the American founders' understanding of the importance of religion to human, social, and political flourishing. The First Amendment makes clear that it sought to protect "the free exercise" of religion, or what might be called "free exercise equality." Free exercise is the liberty of persons to reach, hold, practice and change beliefs freely according to the dictates of conscience. The Free Exercise Clause prohibits government interference with religious belief and, within limits, religious practice. "Freedom of religion means freedom to hold an opinion or belief, but not to take action in violation of social duties or subversive to good order." The Free Exercise Clause offers a double protection, for it is a shield not only against outright prohibitions with respect to the free exercise of religion, but also against penalties on the free exercise of religion and against indirect governmental coercion. Relying on Employment Division v Smith (1990) and quoting from Church of the Lukumi Babalu Aye Inc v Hialeah (1993) the Supreme Court stated in Trinity Lutheran Church of Columbia Inc v Comer (2017) that religious observers are protected against unequal treatment by virtue of the Free Exercise Clause and laws which target the religious for "special disabilities" based on their "religious status" must be covered by the application of strict scrutiny.

Establishment of religion.

The precise meaning of the Establishment Clause can be traced back to the beginning of the 19th century. Thomas Jefferson wrote about the First Amendment and its restriction on Congress in an 1802 reply to the Danbury Baptists, a religious minority that was concerned about the dominant position of the Congregational church in Connecticut, who had written to the newly elected president about their concerns. Jefferson wrote back:

Believing with you that religion is a matter which lies solely between Man & his God, that he owes account to none other for his faith or his worship, that the legitimate powers of government reach actions only, and not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should "make no law respecting an establishment of religion, or prohibiting the free exercise thereof", thus building a wall of separation between Church & State. Adhering to this expression of the supreme will of the nation in behalf of the rights of conscience, I shall see with sincere satisfaction the progress of those sentiments which tend to restore to man all his natural rights, convinced he has no natural right in opposition to his social duties.

In Reynolds v United States (1878) the Supreme Court used these words to declare that "it may be accepted almost as an authoritative declaration of the scope and effect of the amendment thus secured. Congress was deprived of all legislative power over mere  opinion, but was left free to reach  actions which were in violation of social duties or subversive of good order." Quoting from Jefferson's Virginia Statute for Religious Freedom the court stated further in Reynolds:

In the preamble of this act ... religious freedom is defined; and after a recital 'that to suffer the civil magistrate to intrude his powers into the field of opinion, and to restrain the profession or propagation of principles on supposition of their ill tendency, is a dangerous fallacy which at once destroys all religious liberty,' it is declared 'that it is time enough for the rightful purposes of civil government for its officers to interfere  when  principles break out into overt acts against peace and good order.' In these two sentences is found the true distinction between what properly belongs to the church and what to the State.

A April 22, 1885, cartoon from the Puck magazine depicting an army of clergymen assaulting a fortress defended by newspaper editors including from Puck, while atop a hill in the background a statue labeled "Constitution" that states "Congress shall make no law respecting an establishment of religion" can be seen.

Reynolds was the first Supreme Court decision to use the metaphor "a wall of separation between Church and State." American historian George Bancroft was consulted by Chief Justice Morrison Waite in Reynolds regarding the views on establishment by the Founding Fathers. Bancroft advised Waite to consult Jefferson and Waite then discovered the above quoted letter in a library after skimming through the index to Jefferson's collected works according to historian Don Drakeman.