Koster switches to Democratic Party in likely bid for Missouri AG

COLUMBIA, Mo. (AP) -- Sen. Chris Koster announced Wednesday that he was switching from the Republican to the Democratic Party, as he prepares for a likely run for attorney general.

Koster said he has determined that he is more aligned with Democrats than Republicans on several issues, including stem cell research, workers' rights, minimum wage and leaving intact Missouri's current judiciary system.

"Today, Republican moderates are all but extinct. On so many of the critical issues of our day it has been Democrats and not Republicans who have stood by my side," Koster said at a news conference at the University of Missouri-Columbia, where he got his bachelor and law degrees.

He stopped short of declaring his intent to run for attorney general, but he has formed a campaign committee for an unspecified statewide office in 2008 and said he does not intend to seek re-election in the Senate.

Koster has angered some in the Republican Party for his ardent support of stem cell research. Some anti-abortion organizations believe a certain form of stem cell research destroys life at its earliest stages.

Jared Craighead, executive director of the Missouri Republican Party, said Koster's decision to switch parties was a strategic move, made because Koster thinks it will be easier to win the Democratic primary in the attorney general's race. The incumbent, Democrat Jay Nixon, plans to seek the governor's office.

"Chris is a personal friend of mine, but I fear he has blinded himself with his desire for higher office and the hollow promises of Jay Nixon's political machine rather than keeping his commitment to the constituents who elected him to represent them," Craighead said in a written statement.

He also said Koster should resign from the Senate and run as a Democrat in a special election.

Koster also had stops planned later Wednesday in his hometown of Harrisonville and in St. Louis, where he went to high school.

In a letter late Tuesday, he told Republican Senate leaders that he was resigning his post as majority caucus chairman.

"Despite the circumstances surrounding this letter, it has been an honor to serve with you in this capacity," he wrote.

Koster's campaign finance reports show he has raised $713,262 for an unspecified statewide office.

Among his major contributions is $125,000 in January from James Stowers -- founder of the Stowers Institute for Medical Research in Kansas City. Stowers financed most of the $30 million campaign for last year's narrowly approved constitutional amendment protecting the ability to conduct stem cell research.

A passionate speech by Koster two years ago helped stall a bill that would have banned a certain kind of embryonic stem cell research.