The second reason is more fundamental. Indeed, it’s an indispensable part of what makes America exceptional. The idea of America as a haven not only for the poor and oppressed but also the skilled and ambitious is deeply ingrained in our national spirit. 

Spurning immigrants, even if they’ve entered illegally, clashes with our identity. “The laws, culture, and traditions that our Anglo-Protestant founders gave us aren’t meant to exclude and divide,” writes Catholic archbishop José H. Gomez of Los Angeles in his new book Immigration and the Next America. “They are meant to include and unite.” Nativism is “a heresy,” he says, “a perversion of the American creed.” Gomez, at 34, emigrated from Mexico.

America isn’t morally obligated to usher in immediately everyone who shows up at our borders. But we should recognize why they come. It’s more than a job they want. They want to decide their destiny in life. Their hopes are basically the same as those of earlier immigrants—our parents and ancestors.

One measure of America’s embrace of immigrants, after a grace period, is how frequently we talk about the success of the foreign-born, the Andrew Carnegies, the Henry Kissingers, the Hakeem Olajuwons. I still chuckle at the joke about an immigrant who was amazed at the hospitality at a big league baseball game. The crowd began a song by asking, “José, can you see?” To me, that’s affectionate, not demeaning.