Remember the days when conservatives deployed an endless series of wedge issues to splinter the Democratic coalition -- peeling white moderate voters off from liberals? Well, now the shoe's on the other foot.
The brewing civil war in the GOP between Tea Party extremists and more normal conservatives hit a boiling point over the past few weeks. But President Obama is poised to keep things boiling by pushing immigration reform to the top of Washington's agenda.
Get ready for more internecine warfare on the right, as Republicans who want to win elections again square off against their more purist right-wing colleagues. And get ready for a replay of the clash between business, which likes immigrants, and Tea Party legislators who speak for white heartland xenophobes.
Why should Americans who care about a functional political system be rubbing their hands with glee at what's coming? Because wedges in political parties can force them to choose between competing positions and to change course in a more moderate direction. That's what happened to the Democrats two decades ago. After being pummeled with wedge issues starting in the late 1960s, Democrats were open to the ideas of Bill Clinton and the DLC for moving to the center to win back moderates.
It's easy to imagine something similar happening on the right. The Republican fratercide can't go on forever, with a splintered party losing more big legislative fights and more elections. At some point, the Tea Party types will either be marginalized or will self-moderate, as many liberals came to do during the 1990s.
The immigration debate offers another chance to push that reckoning to a head.