AMERICANS, we are losing Mexicans. According to the Pew Hispanic Center, more Mexicans exited the United States than entered it from 2005 to 2010. I conclude that aggressive tactics to encourage "self-deportation" work. Deportation (the regular jackbooted kind), border walls, surveillance drones, harassment of brown people with or without suspicious accents, all of it! And recessions. Recessions, too. Recessions mostly, maybe. And maybe not. America's economic downturn is a big part of the story, but it's not the whole story. Mexico has an economy, too. And it's not going so badly there, which is one reason we should not expect Mexican immigration to return to trend as American growth and employment returns to trend. As Michael Barone argues:

The Pew analysts hesitate to say so, but their numbers make a strong case that we will never again see the flow of Mexicans into this country that we saw between 1970, when there were fewer than 1 million Mexican-born people in the U.S., and 2007, when there were 12.7 million.

One reason is that Mexico's population growth has slowed way down. Its fertility rate fell from 7.3 children per woman in 1970 to 2.4 in 2009, which is just above replacement level.

Meanwhile, Mexico's economy has grown. Despite sharp currency devaluations in 1982 and 1994, its per capita gross domestic product rose 22 percent from 1980 to 2010.

Mexico, like the United States, experienced a recession from 2007 to 2009. But since then, Mexico's GDP has grown far faster than ours -- 5.5 percent in 2010 and 3.9 percent in 2011.

Mr Barone goes so far as to argue that, since the era of mass Mexican immigration is over for good, the shape of the immigration debate in America will never be the same. "The key immigration issue for the future", Mr Barone maintains, "is whether America, like our Anglosphere cousins Canada and Australia, will let in more high-skill immigrants." I'm not so sure American worries about visits from our Mexican neighbours will fade this much, but it does seem likely that Republicans in this year's primaries have been fanning nativist embers bound to fade, perhaps at great cost to their electoral prospects.

Anti-immigration sentiment is reliably inflamed by recession. A shrinking economic pie inspires paranoia about out-group designs on the natives' dwindling shares. But as growth and employment pick up, Americans will rediscover our traditional expansive spirit of welcome. And as awareness spreads of the retreating tide of Mexican immigration, even the least hospitable among us will lighten up a little.

Yet Mitt Romney is stuck with debate clips in which he goes on about "self-deportation" and bullies Rick Perry for displaying the compassion and good sense born of his experience governing a border state. Mr Romney needs to improve his position among Hispanic voters; he trails Mr Obama by about 40% in the polls. And, as my colleagues point out in this week's print edition, Hispanics "account for over 20% of the population in several swing states, including Colorado, Florida, Nevada and New Mexico" and Democrats are looking hungrily at Arizona, which has put in place controversial measures against illegal immigration now before the Supreme Court. So you can be sure Mr Romney is giving this Etch-A-Sketch a good shake. Will it help? Michael Tomasky of the Daily Beast says it'll help a little, but not a lot; Mr Romney certainly won't match George W. Bush's 42% of the Hispanic vote:

Romney ... will make some moves that will impress the largely white commentariat, and he'll bump up a little among certain high-income Latino demographics. But average Latino voters, men and women who work really hard every day for white bosses, are just going to find that he reminds them too much of the guy who docks their pay when the bus comes late. And they won't be wrong—he basically is that guy. There's no overcoming that. He's a 31 percenter at best.

My colleague adduces some supporting considerations:

... Democrats are doubtful that Republicans can win over many Hispanic voters. “You can't do it when at a very baseline level you make American citizens feel unwelcome in their own country,” says Joaquin Castro, a Democratic state representative from San Antonio, Texas. It will not help that in the middle of the campaign the Supreme Court will draw attention once again to the Republicans' obstreperousness on the issue by ruling on the Arizona law.

Buena suerte, Mr Romney!

(Photo credit: AFP)