First, the realities of demographic change have begun to bite. Since the mid-1990s, the share of nonwhite voters has increased by about three percentage points each presidential election. If America’s demographic composition were the same last year as it was in 1992, Mitt Romney would have won in a landslide. If it were the same as it was in 2000, he would now be president. Instead, Romney secured 59 percent of the white vote — and lost the election by four points.

Second, during the same 20 years these shifts were taking place, elements of the GOP undertook an active campaign to alienate rising demographic groups. It began with Proposition 187 in California, denying public services to illegal immigrants and their families, and continued with restrictive immigration laws in Arizona, Georgia, South Carolina and Alabama. This effort symbolically culminated in Romney’s embrace of “self-deportation” and his loss of the Hispanic vote by 44 points.

From one perspective, immigration restrictionists are correct. In the current political atmosphere — the atmosphere they helped to create — immigrants who become citizens will be deeply suspicious of Republicans. So are current voters who have ties to or sympathy for immigrant communities. The problem is this: While killing immigration reform may slightly extend the viability of the current Republican political coalition, it may seriously undermine the attempt to adjust it.