The 2010 Citizens United decision by the U.S. Supreme Court fundamentally changed U.S. campaign finance laws by saying that corporations, unions, and other organizations have a First Amendment right to spend unlimited amounts of money on political campaigns, as long as the spending is independent and not directly coordinated with candidates or political parties. It allowed for the creation of Super PACs and 501(c)(4)s which can raise and spend unlimited amounts of money to support or oppose candidates. We get an overview of the recent history of campaign finance rules and spending patterns, and learn what campaigns spend all of that money on.