Surprising news late this afternoon: Sen. Byron Dorgan (D-ND) announces that he will not seek re-election in 2010. From the release:

"For the past year, I have been making plans to seek another six-year Senate term in next year's election. Those plans included raising campaign funds and doing the organizing necessary to wage a successful campaign.

Even as I have done that, in recent months I began to wrestle with the question of whether making a commitment to serve in the Senate seven more years (next year plus a new six-year term) was the right thing to do.

I have been serving as an elected official in our state for many years. Beginning at age 26, I served ten years as State Tax Commissioner followed by thirty years in the U.S. Congress by the end of 2010. It has been a long and wonderful career made possible by the people of North Dakota. And I am forever grateful to them for the opportunity.

Although I still have a passion for public service and enjoy my work in the Senate, I have other interests and I have other things I would like to pursue outside of public life. I have written two books and have an invitation from a publisher to write two more books. I would like to do some teaching and would also like to work on energy policy in the private sector.

So, over this holiday season, I have come to the conclusion, with the support of my family, that I will not be seeking another term in the U.S. Senate in 2010. It is a hard decision to make after thirty years in the Congress, but I believe it is the right time for me to pursue these other interests."

We noted before the Christmas break that Dorgan was facing the prospect of a strong challenge from North Dakota's popular GOP governor, John Hoeven. Hoeven hadn't yet announced, and some had begun to doubt he would actually run. But Dorgan's announcement would have to give Hoeven a strong push toward the race.

For Democrats, a logical candidate would be the other member of the state's all-Democratic Congressional delegation, Rep. Earl Pomeroy. But Pomeroy making a run against Hoeven for the Senate seat would put two seats at risk.

The announcement means Dorgan is the first elected incumbent Democratic senator to bow out of a 2010 race (appointed Sens. Roland Burris and Ted Kaufman were not running). Six Republicans announced last year they would not run again, including Florida's Mel Martinez, who resigned early.

Dorgan may not be the last to opt out, with many eyeing Sen. Chris Dodd (D) as a retirement possibility. Democrats might prefer to see that happen, given his weak polling. But the Dorgan decision most certainly qualifies as unwelcome news given the increasingly bleak political climate for the party.

UPDATE: Here's NRSC communication director Brian Walsh's statement:

"North Dakota was always going to be a competitive seat for the Democrats to defend, and Senator Dorgan's retirement now provides us with another excellent pick-up opportunity for Republicans in 2010. This development is indicative of the difficult environment and slumping approval ratings that Democrats face as a result of their out of control tax-and-spend agenda in Washington, and we fully intend to capitalize on this opportunity by continuing to recruit strong candidates who can win these seats in November."