Peggy Noonan digs in and thinks she’s found what is bothering American’s about immigration:

There are a variety of things driving American anxiety about illegal immigration and we all know them–economic arguments, the danger of porous borders in the age of terrorism, with anyone able to come in.
But there’s another thing. And it’s not fear about “them.” It’s anxiety about us.
It’s the broad public knowledge, or intuition, in America, that we are not assimilating our immigrants patriotically. And if you don’t do that, you’ll lose it all. . . .Do we teach our immigrants that this is what they’re joining? That this is the tradition they will now continue, and uphold?
Do we, today, act as if this is such a special place? No, not always, not even often. American exceptionalism is so yesterday. We don’t want to be impolite. We don’t want to offend. We don’t want to seem narrow. In the age of globalism, honest patriotism seems like a faux pas.
And yet what is true of people is probably true of nations: if you don’t have a well-grounded respect for yourself, you won’t long sustain a well-grounded respect for others.
Because we do not communicate to our immigrants, legal and illegal, that they have joined something special, some of them, understandably, get the impression they’ve joined not a great enterprise but a big box store. A big box store on the highway where you can get anything cheap. It’s a good place. But it has no legends, no meaning, and it imparts no spirit.

She continues by calling for a more positive teaching of U.S. history. I’ve got some thoughts on that too.