WASHINGTON (By Howard Fineman, Op-Ed) June 7, 2010 ― If there's one number that should matter most to politicians right now ― in Washington, in Arizona ― it's 83.

That is the percentage of young Hispanic voters who, according to a new Democracia USA survey, worry about being discriminated against. Why so crucial? It's impossible to overstate Hispanic political power: for each of the next 20 years (and in each of the last 10), a half million Hispanic citizens will turn 18 ― voting age.

By midcentury, census data show, Hispanics will be the country's largest ethnic group. By the end of the century, they'll be the majority.

Geography, educational mores, and technology make this group different from earlier immigrant waves. The ideal of assimilation ― Teddy Roosevelt's melting-pot standard ― is outdated in a country where most new immigrants are from next door, urban public schools are not as diverse and rigorous as they once were, and satellites and the Internet keep people tethered to their home culture.

Democracia's poll found, while young Hispanics believe in the American Dream, they recoil at what they see as an obsession with money. They find refuge in an empathetic Hispanic ethos ― and in speaking Spanish. Two thirds referred to themselves as bilingual or bicultural. "When I was growing up in New Jersey, we would run away from our Hispanic heritage," says Jorge Mursuli, a Cuban-American and the head of Democracia.

"With these kids, it's entirely different. They want to ― need to ― embrace Hispanic culture. They feel fortunate to be able to live in two worlds."

That, however, makes them especially sensitive ― and vulnerable ― to an immigration law like Arizona's, which gives police wide latitude to stop anyone they have "reasonable cause" to think is in the country illegally.

Not surprisingly, Hispanics view the law as a license to harass. Still, that hasn't stopped Republican candidates nationwide from tripping over each other as they run to the right on the issue. That's what Sen. John McCain is doing ― rather unconvincingly ― in Arizona to fend off a challenge from onetime congressman J. D. Hayworth.

In California's GOP primary for governor, the formerly anodyne businesswoman Meg Whitman has a spot featuring former governor Pete Wilson calling her "tough as nails" on immigration ― even though or rather, because Wilson is reviled in the Hispanic community for supporting a similarly draconian state law in 1994.

And in Kentucky, the ineffable Rand Paul suggests denying citizenship to American-born children of illegal immigrants ― which might sound vaguely reasonable until you realize that it violates the Constitution.

Arizona's law is due to go into effect July 29; between now and then, it will likely get a second wind on cable TV as it takes center stage in the courts and on the campaign trail. Polls show strong national support for the law among non-Hispanic voters, especially older ones, but even stronger opposition among Hispanics, especially younger ones.

These tectonic plates are headed toward one another. An earthquake is coming, perhaps this fall, and the guy on the fault line is President Obama. Most Democrats, especially in swing districts, want to steer clear of the issue; they're hunting for conservative votes in a bad year.

But if Obama doesn't challenge the law, he risks losing a generation of Hispanic voters. Pollster Sergio Bendixen, who conducted the Democracia survey, says, "Hispanics want to see if he's an honest and true friend. It's not about the details of legislation or lawsuits, it's about feeling welcome here."

Obama, as is his wont, is mulling what to do. He could pledge not to cooperate, meaning he would direct the feds not to deport any illegals that Arizona rounds up. "That would, in effect, kill the law," says Thomas A. Saenz of the Mexican-American Legal Defense Fund. (A coalition of civil-rights and Hispanic groups has filed suit against the law in a Phoenix federal court, and they were planning last week to ask for a preliminary injunction. The Justice Department is "considering" its options, say two White House officials who didn't want to be named discussing legal strategy.)

Or Obama could push fellow Democrats in Congress to pass a comprehensive immigration-reform bill, which would include a path to citizenship for millions of undocumented aliens. In both the campaign and his first year in office, it's what he promised to do. "I want to believe in that person," says Democracia's Mursuli. And, it appears, there's no shortage of young Hispanic voters who do, too.