Sen. Mark Dayton, D-Minn., announced Wednesday that he will not run for re-election in 2006.

“I do not believe that I am the best candidate to lead the (Democratic-Farmer-Labor) Party to victory next year,” he said in a statement.

In 1990, he was elected state auditor. Dayton, 58, was elected to his U.S. Senate seat in 2000 and is serving his first term.

A poll conducted by the Star Tribune last month found that Dayton’s approval rating had dropped from 58 percent last year to 43 percent this year.

That, combined with Minnesota’s tendency to be a swing state and the criticism Dayton received for closing his office before the 2004 election, made his seat vulnerable, said Kathryn Pearson, a University political science professor.

“I think the bottom line is he realized it would be a really tough seat to hold on to,”

Pearson said. “He had the most-vulnerable seat coming up in 2006.”

Pearson said that while Dayton’s voting record did not put him in danger, he was not a clearly visible leader in the Senate either.

The Democratic Party might have a better chance of winning in the 2006 election without Dayton on the ticket, she said.

The DFL Party released a statement after Dayton’s announcement stating: “Mark has always led from his heart, and his decision today is no different.”

University-DFL President Austin Miller said who will emerge as candidates to run for the party is anybody’s guess.

He said he does not think anyone is “groomed” to be a Democratic candidate. He also said he wished Dayton would have made his decision earlier.

But Miller said Minnesotans should be proud of Dayton and the way he maintained individuality.

Tonya Tennessen, managing communications director for the DFL Party, said Wednesday was not a day to talk about potential candidates – it was a day to thank Dayton for his service.

Pearson said that independent of who runs, the 2006 election will be competitive and expensive. Both parties will spend “a ton of money,” she said.

Tony Richter, College Republicans chairman, said that while he wished Dayton well, he is glad he is not running again.

“I think it’s time for a change,” he said. “Hopefully, we can get someone in there who can actually represent Minnesota values.”

In a released statement, Sen. Norm Coleman, R-Minn., said, “Sen. Dayton has been a good and decent public servant with a big heart for the people of Minnesota.”

Coleman said he imagined it was a difficult day for Dayton.