By Paul Krugman

The Tenement Museum, on the Lower East Side, is one of my favorite places in New York City. It’s a Civil War-vintage building that housed successive waves of immigrants, and a number of apartments have been restored to look exactly as they did in various eras, from the 1860s to the 1930s (when the building was declared unfit for occupancy). When you tour the museum, you come away with a powerful sense of immigration as a human experience, which — despite plenty of bad times, despite a cultural climate in which Jews, Italians, and others were often portrayed as racially inferior — was overwhelmingly positive.

I get especially choked up about the Baldizzi apartment from 1934. When I described its layout to my parents, both declared, “I grew up in that apartment!” And today’s immigrants are the same, in aspiration and behavior, as my grandparents were — people seeking a better life, and by and large finding it.

That’s why I enthusiastically support President Obama’s new immigration initiative. It’s a simple matter of human decency.

That’s not to say that I, or most progressives, support open borders. You can see one important reason right there in the Baldizzi apartment: the photo of F.D.R. on the wall. The New Deal made America a vastly better place, yet it probably wouldn’t have been possible without the immigration restrictions that went into effect after World War I. For one thing, absent those restrictions, there would have been many claims, justified or not, about people flocking to America to take advantage of welfare programs.

Furthermore, open immigration meant that many of America’s worst-paid workers weren’t citizens and couldn’t vote. Once immigration restrictions were in place, and immigrants already here gained citizenship, this disenfranchised class at the bottom shrank rapidly, helping to create the political conditions for a stronger social safety net. And, yes, low-skill immigration probably has some depressing effect on wages, although the available evidence suggests that the effect is quite small.

So there are some difficult issues in immigration policy. I like to say that if you don’t feel conflicted about these issues, there’s something wrong with you. But one thing you shouldn’t feel conflicted about is the proposition that we should offer decent treatment to children who are already here — and are already Americans in every sense that matters. And that’s what Mr. Obama’s initiative is about.

Who are we talking about? First, there are more than a million young people in this country who came — yes, illegally — as children and have lived here ever since. Second, there are large numbers of children who were born here — which makes them U.S. citizens, with all the same rights you and I have — but whose parents came illegally, and are legally subject to being deported.

What should we do about these people and their families? There are some forces in our political life who want us to bring out the iron fist — to seek out and deport young residents who weren’t born here but have never known another home, to seek out and deport the undocumented parents of American children and force those children either to go into exile or to fend for themselves.

But that isn’t going to happen, partly because, as a nation, we aren’t really that cruel; partly because that kind of crackdown would require something approaching police-state rule; and, largely, I’m sorry to say, because Congress doesn’t want to spend the money that such a plan would require. In practice, undocumented children and the undocumented parents of legal children aren’t going anywhere.

The real question, then, is how we’re going to treat them. Will we continue our current regime of malign neglect, denying them ordinary rights and leaving them under the constant threat of deportation? Or will we treat them as the fellow Americans they already are?

The truth is that sheer self-interest says that we should do the humane thing. Today’s immigrant children are tomorrow’s workers, taxpayers and neighbors. Condemning them to life in the shadows means that they will have less stable home lives than they should, be denied the opportunity to acquire skills and education, contribute less to the economy, and play a less positive role in society. Failure to act is just self-destructive.

But speaking for myself, I don’t care that much about the money, or even the social aspects. What really matters, or should matter, is the humanity. My parents were able to have the lives they did because America, despite all the prejudices of the time, was willing to treat them as people. Offering the same kind of treatment to today’s immigrant children is the practical course of action, but it’s also, crucially, the right thing to do. So let’s applaud the president for doing it.