Sarah Palin just offered a surprise endorsement of insurgent Delaware Senate candidate Christine O'Donnell, calling in to Sean Hannity's radio show to offer her support. The news broke mainly on Twitter, after O'Donnell and Hannity tweeted it.

Dave Weigel points out some back-story here: O'Donnell's campaign manager, Matt Moran, comes from the campaign of Dave Hoffman, the Conservative Party candidate in upstate New York who briefly captivated people who follow special House elections when he ran a campaign, fueled party by Palin's endorsement, that eventually forced the Republican candidate out of the race and handed the seat to Democrats. It was one of Palin's early forays into the endorsment game, and the discussion that surrounded that race in November 2009 centered on the rising influence of Palin and Tea Pariers in campaigns across the country.

Palin's endorsement (I suspect) may have had more to do with the Tea Party Express. That group, which has spent hundreds of thousands of dollars on conservative candidates this year, put the Delaware Republican Senate primary on the map by endorsing O'Donnell over frontrunning moderate Republican Rep. Mike Castle and pledging to spend $250,000 on her (whether it hits that goal is probably up in the air).

Tea Party Express seems to have a good relationship with Palin, who has boarded its tour bus. It endorsed Joe Miller in Alaska not terribly long after Palin endorsed him, and the group was aware that Palin was eager for it to get involved.

But in Delaware, the roles appear to be switched.

In Alaska, the group dedicated around $600,000 to Miller's campaign, evidently with Palin's nudging, and then Palin didn't really campaign for Miller. She held no public events or private fundraisers, though she did record a robo-call for Miller and appear in Tea Party Express ads for him. Palin had nudged, and the group had backed her up.

In Delaware, the situation is opposite: Tea Party Express could use some help getting O'Donnell elected (it hasn't gotten any from other groups), and Palin has delivered some support with this endorsement.

There was less apparent cost to endorsing O'Donnell when Tea Party Express did it on August 30, just over two weeks ahead of the September 14 primary date. At that time, the national media was unaware of all the issues O'Donnell is now facing: the money she owed to the IRS (possibly not her fault), paying half her rent with campaign money because her apartment doubles as her campaign headquarters, selling her house to her campaign lawyer in 2008 as she faced action by her mortgage holder. All these things have been used to hit O'Donnell, and hit her with force, since Tea Party Express made her candidacy a national story.

Now Palin jumps in after all that has been aired. She offers this endorsement knowing that baggage comes with it. Lots of people will question why Palin is endorsing O'Donnell, given all that's emerged about O'Donnell's profile as a candidate.

Tea Party Express endorsed O'Donnell for its own reasons, and they serve as decent reasons for Palin just the same. It saw an opportunity to knock off a moderate Republican in Castle, and, if not, to at least make some waves and push Republicans across the country further to the right. As of now, many GOP candidates are toeing the Tea Party line on a host of issues, to the point where it's difficult to tell who's a "Tea Party candidate" and who's not.

But here's one theory: perhaps this endorsement is simply repayment to the group for essentially winning the Alaska GOP Senate primary at her behest.

We want to hear what you think about this article. Submit a letter to the editor or write to