Article 18 of the UN Declaration on Human Rights:

Everyone has the right to freedom of thought, conscience and religion; this right includes freedom to change his religion or belief, and freedom, either alone or in community with others and in public or private, to manifest his religion or belief in teaching, practice, worship and observance.

If we all lived completely alone, in vacuums that somehow, magically, never interacted with one another, then perhaps rights such as this could go without debate, argument, or conflict. But in what I am 100% sure will come as a shock to some listeners, we all live in communities of some kind. And where those communities exist, conflicts arise.

In this situation, definitions can be quite helpful – and some do exist. The most succinct definition I’ve been able to find is from the book Religious Freedom under the Personal Law System by Farrah Ahmed. Quote:

A person has religious autonomy when they shape their own religious life.

Religious persecution has a number of definitions out there. In the book Religious Persecution and Political Order in the United States, author David T. Smith outlines, quote:

violence or discrimination against members of a religious minority because of their religious affiliation. Persecution involves the most damaging expressions of prejudice against an out-group, going beyond verbal abuse and social avoidance. It refers to actions that are intended to deprive individuals of their political rights and to force minorities to assimilate, leave, or live as second-class citizens.

So – in some ways – these two concepts are not so much a continuum where there is a single line. Instead, these concepts are two ends of a spectrum, which sometimes come in to conflict.

The Pew Research Center, our old friends, refer to two different types of restrictions on religious beliefs — governmental restrictions and social hostilities.  In June of 2018, their report on worldwide religious restriction found that, quote:

In total in 2016, 83 countries (42%) had high or very high levels of overall restrictions on religion – whether resulting from government actions or from hostile acts by private individuals, organizations and social groups – up from 80 (40%) in 2015 and 58 (29%) in 2007.

Which, frankly, is all in theory. There are plenty of not-so-theoretical examples that legal systems around the world have been asked to judge about what counts as an unreasonable restriction, and what is within someone’s rights or purviews. There’s extreme examples like genocides and massacres based on religious differences, or laws that out