The anger within the activist class has already caused political casualties, from Utah's Bob Bennett to Indiana's Richard Lugar. It has also forced incumbent Republicans to change their tune, in hopes of avoiding the same fate. Senate Minority Leader Mitch McConnell, the picture of the Republican establishment, has hired Rep. Ron Paul's campaign manager — one of the party's best field operatives, to be sure, but one who brings tea party credibility to a candidate clearly worried about his right flank in the meantime. Aides to Sen. Lamar Alexander have polled Tennessee's Republican voters several times, and they are notably relieved every time Alexander scores high approval ratings there. In the House, the most conservative wing of the Republican conference has gone from occupying the fringes with little influence to dominating the party's agenda.

If Republicans do lurch to the right, history suggests they will be vindicated in the near-term. The mid-term election under a second-term president is typically disastrous for the incumbent party as the six-year itch takes effect. Even if Republicans can't win back the Senate this year, their chances against the Democrats swept in by the Obama wave in 2008 will be strong.

By 2016, Republicans searching for a presidential nominee may incorporate two lessons from the previous two election cycles into their decision: 2012 will hint that moderates unable to articulate the most conservative vision can't win nationally, and 2014 will show conservatives can win. That would seem to buoy any of the more conservative candidates who might run for president — and Rick Santorum has already shown up in Iowa twice since dropping out of the presidential race to campaign for other Republican causes.