-- Michael Bennet, the senator appointed to fill the Colorado seat held by Ken Salazar, faces a strong challenge from Jane Norton, the popular former lieutenant governor. She'll probably win.
-- Arkansas Sen. Blanche Lincoln has defied her state one too many times when she voted for health care. She'll pay the price in November.
-- As will Harry Reid, who lags behind both of his possible opponents. With his son running for governor, Reid may not even run for fear of dragging his boy down with him. The family needs one of them to be in office. It's how they make their money.
That brings the GOP to 45 seats.
Next are two races where the Republican has a good chance -- Pennsylvania and Illinois.
-- In Pennsylvania, part-time Republican, part-time Democrat and full-time opportunist Arlen Specter is running for re-election in a primary against Democratic Rep. Joe Sestak. Don't count on Specter staying in the race. And count on his losing the primary if he does. The Republican, Pat Toomey, should win the race in November, easily against Specter, with more difficulty against Sestak.
-- Obama's Senate seat is up in Illinois, and Mark Kirk, the Republican congressman who has taken the lead in pushing for vigorous sanctions against Iran, is tied with his potential Democratic rivals. We should pick up both seats.
That'd be 47.
Then there is California, where Carly Fiorina is only a few points behind Barbara Boxer. It's hard to imagine California going Republican -0 but easier than to have visualized Massachusetts doing so. That would make 48.
But then the Republican Party runs out of candidates. It doesn't have anyone strong to go up against Gillibrand, Bayh, Murray, Widen or Feingold. Anyone want a Senate seat? Gillibrand (or Harold Ford, if he wins the primary) will not be hard to defeat. Murray won with only 55 percent of the vote last time. Wyden got only 54 percent. Bayh is from solidly Republican Indiana, and Feingold is too liberal for anyplace this side of Cuba.
Hopefully, the Brown race will kindle the fires of ambition in incipient candidates in these key states. They need to win at least three of the five to take control.