Sen. Mel Martinez, R-Fla., won't seek reelection in 2010. This is a big one: Martinez may just be a freshman, but he was secretary of housing and urban development at the start of the Bush administration, and he did a stint as chairman of the Republican National Committee. Plus, Democrats now have a good shot at getting the seat -- which was Bob Graham's -- back.
Martinez would have had a tough time winning a second term; his approval rating, according to a November Quinnipiac University poll, was just 42 percent, and a plurality of voters, 38 percent, said he didn't deserve to be reelected.
His unpopularity won't help whatever Republican candidate runs to succeed him. Neither will Florida's changing demographics -- as I discussed in this article last month, the state's traditionally Republican Hispanic community was a key swing vote in this election, and actually delivered Florida to Barack Obama. Martinez is Cuban-American; the state's Hispanic politics used to be dominated by Cuban exiles, who are generallly conservative, but no more.