President Obama wrapped up his remarks at the G20 summit in Turkey this morning with a searing indictment of American unwillingness to take in Syrian refugees — and, in particular, the idea (increasingly popular among Republicans) that the US should only take in refugees if they're Christians.

But Obama's remarks weren't just a rebuke to Republicans. They were a defense to the rest of the world — including the other world leaders at the G20 summit — of America's historical role as a champion of refugees, and a refusal to give away that mantle.

The position Obama is criticizing is quickly becoming the leading position of the Republican field. Both Ted Cruz and Jeb Bush said over the weekend that in the wake of the Paris attacks, the US should limit refugee admissions to Christians (who make up about 10 percent of Syria's population).

Obama's argument, given in Turkey at the G20 summit, deliberately casts this as an affront not only to American values, but to universal values of pluralism, freedom of religion, and nondiscrimination. But it goes to the heart of America's role in the world: For as long as there have been internationally recognized refugees, America has been the country most welcoming to them.

America's legacy of taking in non-Christian refugees

The international refugee system was established in the wake of the Holocaust, after thousands of Jews attempting to flee Nazi Germany were turned away by the United States and other countries. (Ironically, one of the justifications for turning away ships of fleeing Jews was that they had somehow been "infiltrated" by Nazi spies.) Since then, however, the US has been the world's leader in resettling refugees so they can make a new life in another country. Historically, half or more of all refugees who have been permanently resettled have gone to the United States.

Most of those have been non-Christian. The most famous immigrations of refugees in US history — Vietnamese and Cambodian refugees fleeing communist Southeast Asia in the 1970s after the fall of Saigon; Russian Jews fleeing the Soviet Union in the late 1980s; and the late 1990s, when the US brought 20,000 ethnic Albanian Muslims to Fort Dix for temporary housing — have been of non-Christians. `

President Obama is correct that the refusal to discriminate against people on the basis of their religion is, theoretically, one of the values that distinguish the pluralistic "West" from extremists like ISIS. But some Western countries have taken that responsibility more seriously than others.

The United States isn't just a country that prides itself on freedom of religion, and refuses to impose "religious tests" on candidates for office. It's also the country that has been, for decades, the world's leader in giving a new home to those fleeing violence and persecution. Refusing to take non-Christians would challenge both of those legacies.

If Cruz and Bush think that America ought to stop being the world's leader in taking in refugees, perhaps they should state that outright and it should be debated in the open. But what they're proposing is a way of ending that commitment in practice, while still allowing themselves to believe that the US is willing to welcome people who are suffering abroad.