Democrats will react with thunderous outrage if the court upholds the Arizona law — but if you stand outside the back room where the pollsters and campaign strategists work, you might hear the slapping of high-fives. Anything that draws attention to the Republican Party’s extremist position on immigration will only reinforce a tendency that Mitt Romney recently characterized as “doom” — the headlong rush of Latino voters into a waiting Democratic embrace.

Barack Obama won a remarkable two-thirds of the Latino vote in 2008. This year, according to the polls, he’s running even stronger among the biggest minority group in the country. If Republicans don’t find a way to win more Latino support, Obama will be hard to beat. In the long term, if Latinos become a more or less permanent Democratic constituency like African Americans have, the GOP will inexorably go the way of the Whigs.

So that is what this year’s immigration “debate” will be about: how to reap political gain and avoid political loss.