Washington (CNN) -- Republican Sen. Olympia Snowe of Maine announced Tuesday she will retire rather than seek re-election this year, surprising colleagues and perhaps casting the future of her seat in doubt. The decision was made "after an extraordinary amount of reflection and consideration," she said in a statement. Snowe, who turned 65 last week, was first elected to the U.S. House in 1978 and then to the Senate in 1994. She is the first woman to serve in both chambers of a state legislature and the U.S. Congress. Snowe was known as a moderate who sometimes sided with Democrats in the increasingly partisan environment of Washington politics.
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White House praises Sen. Olympia Snowe for her bipartisan leadership
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Snowe known as moderate Republican who sometimes votes with Democrats
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Maine GOP chairman says the decision is going to shake up state politics
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She cites the partisan divide in Washington as a reason for retiring
@placeholder not only hold a strong registration advantage in the state, but this is a state that the president won by 17 points in 2008 and will likely win by a significant margin this year, as well."