Jonathan Chait has a great feature in New York Magazine on the frantic fear among Republicans that this is their last chance to stop the leftward drift of the United States as it becomes younger, browner, and more educated. He zeroes in on the apocolyptic rhetoric of GOP lawmakers and presidential candidates, but his most important point, I think, is this:
The most widely agreed-upon component of any such undertaking was a concerted effort to win back the Hispanic vote. It seemed like a pure political no-brainer, a vital outreach to an exploding electoral segment that could conceivably be weaned from its Democratic leanings, as had previous generations of Irish and Italian immigrants, without altering the party's general right-wing thrust on other issues. […]
In the wake of [John McCain's] defeat, strategists like Karl Rove and Mike Murphy urged the GOP to abandon its stubborn opposition to reform. Instead, incredibly, the party adopted a more hawkish position, with Republicans in Congress rejecting even quarter-loaf compromises like the Dream Act and state-level officials like Jan Brewer launching new restrictionist crusades. This was, as Thomas Edsall writes in The Age of Austerity, "a major gamble that the GOP can continue to win as a white party despite the growing strength of the minority vote."
The key thing to remember about the Democratic, "majority-minority" future is that it's not inevitable. Yes, Asians and Latinos will continue to move to the United States in large numbers, and yes, growing intermarriage rates will diversify the population even further.
But there's nothing about either trend that guarantees Democratic dominance; if Republicans were to run counter to the administration-which has set a record for deportations-embrace comprehensive immigration reform and put themselves on the side of open immigration law, then they could build an enduring advantage with immigrants of all stripes, and maintain a competitive edge in future elections.
By digging in and demonizing Latino immigrants, conservatives have convinced many that the Republican Party stands explicitly against their interests. And in the process, they have helped shape a discrete "Latino bloc" which leans heavily toward Democratic candidates at all levels of electoral competition. Even if they win in November, this will hurt their party for the forseeable future.