No one is sure how vulnerable Gov. Chet Culver will be in 2010, when he will likely run for reelection, but this week, we have a better picture of which Republican political figures might challenge him.

There’s Bob Vanderplaats, a well-connected social conservative who was 2006 GOP gubernatorial nominee Jim Nussle’s running-mate.  Vanderplaats formally launched an exploratory committee yesterday because, well, he did not already have a committee that could raise money for his statewide campaign.  His biggest challenge?  Prove to GOP primary voters that he’s more than a single-issue candidate, that he is a serious, electable candidate statewide.

Then there are Secretary of Agriculture Bill Northey and State Auditor David Vaudt, two Republicans who have proven they can win statewide.  In recent interviews, neither would rule out challenging Culver in 2010.  You can take them at their word that they haven’t decided whether to run yet, but it’s a safe bet that they’d be happy to accept contributions to their already-existing campaign committees if you’d like to get in on the ground floor…  Their biggest challenges?  Balancing the desire to wait and see how vulnerable Culver is with the need to enter the race early to sew up the GOP nomination.

Will both Northey and Vaudt run?

Not likely.  They would have to decline to run for reelection to their current offices before getting very far in the gubernatorial race.  Why would both of them give up their jobs just so one of them could lose in a messy primary and have nothing?  Both of them stand very good chances of being reelected in their current jobs if they want to keep them.  The only way I see them both running is as a ticket, which, now that I mention it, is an interesting possibility, but I have no actual evidence that a deal is in the works.

How vulnerable is the governor?

The easy answer is that we’re too far from November 2010 to know.  But we do know a few things.  Midterm elections are typically bad for the political party that controls the White House, so there is some thought that Culver will be vulnerable in 2010 for that reason alone.  Some also believe that in times of economic uncertainty, voters tend to blame the party that’s in power.  Of course, there is also the conventional wisdom that says that voters tend to trust Democrats more than Republicans when they are worried most about making ends meet.  Many questions remain.