Conservatives usually believe in American exceptionalism, and in upholding the Constitution. Which is why it's strange to see so much conservative ebullience over Donald Trump's proposal to end birthright citizenship.

It's not news that there are a significant number of Americans who are anxious about immigration — illegal and otherwise — and that they exert considerable political clout (though ultimately less than is sometimes breathlessly suggested). And many of those people fret about so-called "anchor babies." The problem with "anchor babies" is that they're a myth. (Trust me. As a Frenchman with a fertile wife who often wanted to emigrate to the U.S., I did the research.)

This fight therefore nicely serves to highlight the fact that most (though not all) fears related to immigration belong more to the realm of fantasy than reality.

But it also illustrates something else: how the restrictionist position is all too often born of a lack of confidence in the American project.

After all, the two are inseparable. Birthright citizenship says, quite explicitly, "The American project is so strong, our culture is so strong, our values are so strong, that any baby born on our soil, no matter where his parents come from, will ultimately grow up to be a well-adjusted American, so that we don't need to wait for him to prove himself to extend citizenship."

In contrast, the movement to end birthright citizenship says, essentially, "Nope, sorry, that's not true. We can't do it. We can't do it anymore."

Which, again, goes to highlight the tension between extreme restrictionism in immigration and conservative values. Conservatives typically display above average, not below average, confidence in the American project and in the capacity of judicious applications of American patriotism to solve problems.

There's another funny intersection between birthright citizenship and the conservative worldview, and I have an unusual window into it. As I said, I'm a Frenchman. France and the United States are unusual in both being nations explicitly founded (or refounded) on Enlightenment values. And one trait they share is that they both instituted birthright citizenship.

One reason was the Enlightenment-driven belief, over and against the feudalism that prevailed in most places in Europe, that citizenship depended on a social contract, not a bloodline, and that your parentage should not therefore change your citizenship status.

But there was another reason (and here lies an entire critique of the Enlightenment, which is a whole 'nother can of worms), a reason we're not too comfortable with today: empire. The institution of birthright citizenship in France was enacted by France's revolutionary government and ratified by Napoleon's civil code, partly so citizens could be pressed into duty in the army. As France expanded, so did its citizenship rolls, as did its citizen army, as did its military might, all in a virtuous cycle (virtuous, at least, from Napoleon's perspective).

The U.S. enacted birthright citizenship for different reasons, to ensure the citizenship of freed slaves after the Civil War. But the point is that birthright citizenship is historically associated with confidence in the national project, perhaps even supreme confidence.

Oh, and how did it do in France? Well, we got scared of immigrants, so we got rid of birthright citizenship piecemeal over the past few decades.

So here's the other odd thing about the birthright citizenship debate: American conservatives saying they want to be more like France. Kudos!