Sen. Lindsey Graham was shocked — shocked — that Democrats would force a vote on the Dream Act knowing they would lose. “You’re not doing this to advance the issue,” sputtered the South Carolina Republican. “You’re doing it to advance your situation politically.”

Of course Democrats were trying to profit politically. They were showing Hispanic voters that Republicans like Graham are blocking the road to immigration reform. And the only way to clear that road is to make those Republicans pay a price for their position.

As President Obama said after the defeat of the Dream Act, “we have to change the politics.” And the politics, they are a-changin’ — baby by baby, town by town. This year, almost half the children born in America were nonwhite, and eventually Republicans will have to face the question: Which side of history do you want to be on?

The Dream Act is a modest but useful step in dealing with a huge problem: 11 million undocumented immigrants now living in America. The measure would create a path to citizenship for a small slice of that population: young people who come here as children, graduate from high school, commit no serious crimes, and either join the military or complete two years of college.

The legislation makes sense on every level. The Pentagon loves it as a source of new recruits. And it rewards the very virtues that conservatives claim to embrace — diligence, discipline and loyalty. The House passed it easily, and 55 senators voted yes, but that fell five votes short of the number needed to overcome a Republican filibuster.

Graham has always been reasonable on the immigration issue, but hard-line opponents screamed “amnesty” as loudly as they could and threatened reprisals against moderate heretics. All but three Republicans caved to this fear mongering (five Democrats did as well). By comparison, eight Republican senators supported allowing gays to serve openly in the military and 13 backed a new arms-control treaty with Russia. When gays and Russians are more popular than you are, you have a problem.

Obama called the failure of the Dream Act his “biggest disappointment” and vowed to bring it up again next year, but in the short run, the odds are stacked heavily against him. In the new Congress, Republicans will assume more power and anti-reform lawmakers will take over key House committees that handle immigration.

In the long run, however, the odds — and the political landscape — shift sharply. This is not guesswork. These future voters have already been born. This year, the Hispanic population reached just about 50 million, or 16 percent of the country. So Sen. Charles Schumer of New York is deadly accurate in saying, “I don’t think any party can succeed writing off such a large part of America.”

In the last election, Hispanics accounted for only 8 percent of the electorate, but even so, their power was palpable. In California, Nevada and Colorado, their votes helped return Democrats to the Senate, enabling the party to keep control of that chamber.

In the future, this trend will accelerate. Texas gets four new congressional seats, and two of them are likely to be dominated by Hispanic voters. The rapid growth in three other states that gained new seats — Arizona, Nevada and Florida — has also been fueled by Hispanics.

Even South Carolina, Sen. Graham’s home state, is not immune. Spanish signs are sprouting on groceries and gas stations in the smallest rural communities. The workers who pluck chickens and mow lawns and hang drywall probably didn’t vote this year, but they — and their children — will in the future. And they will remember Graham’s “no” on the Dream Act. As demographer William Frey of the Brookings Institution put it, “Savvy politicians ought to be able to understand that in the not-too-distant future these are voters that are going to matter.”

The irony here is that Hispanics are a natural recruiting ground for Republicans. Many are Catholics or evangelical Protestants who share the party’s conservative posture on social issues, and many own small businesses and identify with the GOP’s low-tax, small-government philosophy.

But two of three Hispanics supported Obama in 2008, and almost that many voted for Democrats this year. The reason is clear: The nativist wing of the Republican Party is driving them away.

So Graham’s right. The Democrats were playing politics by forcing a vote on the Dream Act. But Republicans have only themselves to blame. If they keep killing immigration reform, they could be killing their own future.

(Steve Roberts’ new book, “From Every End of This Earth” (HarperCollins), was published in paperback this fall. Steve and Cokie Roberts can be contacted by e-mail at stevecokie@gmail.com.)