The Tea Party and the Republican Party have been forced into a marriage of inconvenience.  Republican candidates need Tea Party support to win many contested elections.  And Tea Partiers, to their dismay, know that the Republican Party, which has disappointed them again and again (take immigration and the deficit, for starters) is still their best bet for getting what they want in terms of policy.

A few purists will probably stay home or vote for a third party in November, rather than pull the lever for Mitt Romney, but I’m confident that most will see the Republican candidate, whatever his deficiencies, as infinitely preferable to Barack Obama.  That’s not so complicated.

Nominating Republican candidates for office, however, is another matter.

The nomination process (caucus or primaries) is a good place for movements to do some damage.  There’s much lower participation than in a final election, and much less visibility.  A smaller group of committed people really can effect influence.  This year, Tea Partiers went after three Republican senators: Olympia Snowe (Maine), Orrin Hatch (Utah), and Dick Lugar (Indiana).  Senator Snowe elected not to run for reelection, severely compromising the prospects of Republicans retaining the seat–and making it more difficult for them to gain control of the Senate.  But Senator Snowe sometimes voted with Democrats.

Senators Hatch and Lugar have always been reliable conservatives.  They are, however, proud of being professional politicians, determined to govern.  This is anathema to Tea Party purists.  Both targets tacked right in response to Tea Party challengers.  It looks like Hatch will survive–and win reelection, but Tea Party enthusiast Richard Mourdock handily defeated Senator Lugar, and probably made the Indiana Senate race newly competitive.  Serving as State Treasurer, Mourdock is no political novice, like, say, Christine O’Donnell; he’s been running for office, often successfully, for more than two decades.  He has, however, clearly articulated a disdain for working with people who disagree with him, claiming to value principle over pragmatism.  He was endorsed by Tea Party favorites, Michele Bachmann, Rick Santorum, and Jim DeMint.  This all sounds great on the campaign trail, but makes governance extremely difficult, ultimately disappointing supporters.

Whether or not the Mourdock for Lugar exchange is a good deal for the Tea Party or the Republican Party is very much an open question.

Senator Jim DeMint (Republican, South Carolina), who has raised and spent millions of dollars on conservative challengers to Republican incumbents, has explicitly argued that having more conservatives in the Senate is far more important than winning Republican control of the body.  (Here, he responds to Christine O’Donnell’s loss in the Delaware senate race.)  He has publicly welcomed new conservatives to the Senate, urging them not to compromise nor to harbor personal ambitions for titles or institutional influence.  Yet he has also used his money and his new allies to improve his own prospects for a leadership position in the Senate.

But professional politicians, including Republican regulars, want to win elections so they can govern.  The battle within the Republican Party, between those who value purity and those who want to govern, is well underway, and likely to get nastier if Republicans make large gains in the next election.

Strict ideological litmus tests sometimes produce candidates who can’t win a general election.  Senator Snowe couldn’t pass such a test, nor could Republican Senators Scott Brown (Massachusetts) or Susan Collins (Maine).  And if Lugar and Hatch don’t pass muster, soon there will be others.

A Republican Party completely captured by the Tea Partiers will be a smaller party.

Ultimately, the resolution will depend upon the voters.  Most Americans quickly grow impatient with movements and politicians who take pride in not delivering.