Many immigrant groups have faced hostility. The Irish did in their time. Jews did. Italians did - and now, Muslim immigrants.

One of Donald Trump's criticisms of President Barack Obama and of Hillary Clinton was that they seemed reluctant to use the words radical Islam. It was not just semantics. Trump said it's important to name the enemy idea and then attack it. Consider the Cold War. The U.S. and its allies waged a kind of propaganda war against the communist idea using radio broadcasts and other tools. Trump has said he'd do the same against Islamic extremism.

Holocaust Museum said ISIS has carried out genocide against the Yazidis, but its investigation did not cover Christian persecution. Now there's concern the U.S. State Department might do the same, limiting any genocide pronouncement to Yazidis without mentioning Christians.

The First Amendment to the Constitution says government can't establish a religion, but neither can it limit the exercise of religion. And that's the issue here. What does it mean to be free to exercise your religion? It's not about what you can believe. It's whether you can act on those beliefs.

As Cuba's leader, Castro answered to no one and allowed no challenge to his authority.

A similar move is underway in the British Parliament. Earlier this month, more than 30 religious leaders and scholars wrote Secretary of State John Kerry asking for a meeting to discuss what's happening to Christians and other minorities. Nina Shea organized the effort.

Many immigrant groups have faced hostility. The Irish did in their time. Jews did. Italians did - and now, Muslim immigrants.