North Dakota Public Service Commissioner Brian Kalk (R) said Wednesday that he's weighing a run against Sen. Kent Conrad (D-N.D.) in 2012. 

The Republican told supporters in an e-mail, obtained by the AP, that he has formed an exploratory committee and has already received encouragement and pledges of financial support from GOP activists ahead of 2012.  

Kalk is a former Marine who was elected to the state's Public Service Commission in 2008. 

Conrad, who is the only Democrat left in North Dakota's delegation after the 2010 midterm elections, has not yet announced his plans for 2012, and there's speculation he could opt to retire. Conrad is the chairman of the Senate Budget Committee.

After Democrat Byron Dorgan announced his retirement from the Senate last year, Republican Gov. John Hoeven easily won an open-seat contest to succeed him. Republican Rick Berg also knocked off Rep. Earl Pomeroy (D-N.D.) this past November to capture the state's at-large House seat.

Even without a top-tier candidate in the race, solid victories in 2010 are a big reason Republicans in the state think the seat will be competitive even if Conrad decides to run again.  

Outside groups have already started spending on ads in the state ahead of 2012. The American Future Fund began running radio spots earlier this month hitting Conrad over the size of the deficit. The Democratic group Commonsense Ten responded with its own spots touting Conrad as a "deficit hawk."