The magic number in the senate, Part Two

In a post called “The Magic Number in the Senate,” I considered the prospects for obtaining, via the November elections, a Senate with enough conservatives to deny the Democrats a filibuster-proof majority. I reckoned that this would require a net pick up of four conservative seats.
Determining that magic number required me to assess which current Republican Senators can be expected usually to vote conservative. I thought that, roughly speaking, all of the current Republican Senators meet this standard, except for Senators Collins, Snowe, and Scott Brown. The magic number of four was computed by adding one seat to these three to provide a margin of error.
I still think my assessment of the current Republican Senators is right (again, roughly speaking), but clearly there are grades of conservative reliability within the Senate GOP ranks.
This point was brought home today, when Republicans George Voinovich (Ohio) and George LeMieux (Florida) broke ranks to vote in favor of an amendment that would create a $30 billion fund for community banks to lend to small businesses. This doesn’t seem like a huge deal (I haven’t examined the merits), but it’s a reminder that “center-right” does not equal “right.” Voinovich has reminded of us of this in the past, as well.
It happens that Voinovich and LeMieux are both stepping down from the Senate, though LeMieux is said to be considering a run in 2012. As I suggested in my earlier post, these seats could fall into more liberal hands — Democrat Lee Fisher in Ohio and independent Charlie Crist in Florida. But the seats would become more conservative if Rob Portman and Marco Rubio were to win them.
Real Clear Politics rates both races as toss-ups. But Portman was 6 points ahead of Fisher in a Rasmussen poll taken in mid-July. Crist and Rubio really do seem to be running about even right now.