If, as widely expected, Charlie Crist decides to run for the Senate as an independent in order to avoid a crushing loss in the Florida primary to Marco Rubio, the man on the hot seat will be George LeMieux.  The man appointed by Crist to fill out the rest of Mel Martinez’ term in the Senate and who will be replaced in this election had been expected to run against Democratic incumbent Bill Nelson in 2012.  For the moment, LeMieux stands behind Crist, but Hotline reports that party loyalty and his own political future will force LeMieux to repudiate his patron and endorse Rubio if Crist bolts the GOP:

LeMieux, who ran Crist’s past campaigns, served as his chief of staff at one point and has largely been seen as Crist’s top political advisor, now has his own political career to consider. Appointed to replace ex-Sen. Mel Martinez (R) last year, LeMieux is said to be taking a serious look at challenging Sen. Bill Nelson (D) in ’12.

But LeMieux now has a choice to make: If Crist bolts the GOP and runs as an independent, LeMieux will have to decide between backing his old friend and angering the very GOP primary voters he’ll need in ’12, or sticking with the party and throwing his pal overboard.

Sources close to LeMieux said they believe he has made his decision, and that he will stick with the party over the person. LeMieux has talked the decision over with his advisors and staff, and they believe LeMieux would endorse ex-FL House Speaker Marco Rubio (R) if Crist makes his switch official.

That will make Crist a very lonely candidate in a three-man race. A defection by LeMieux will probably encourage most of Crist’s staff to go with him, and certainly the donors as well. Crist will hardly be able to shrug off a LeMieux endorsement of Rubio as an example of GOP establishment interference, since LeMieux’s only connection to the GOP establishment has been through Crist himself.

It’s also a bit of a catch-22 for LeMieux. One of the possibilities being offered Crist is a shot at Nelson in 2012. If LeMieux’s opposition to an independent bid convinces Crist to back down in 2010, LeMieux will have made it almost impossible to run himself for the nomination. Crist might well succeed in 2012 if other Republicans don’t challenge for the nomination, as Crist’s approval ratings have remained relative high (55% in this week’s Rasmussen survey) despite his bad showing against Rubio in the primary polling. LeMieux won’t be able to run a credible campaign against Crist in a primary.

It’s hard to imagine that Crist will burn down his entire political career for a one-time shot at losing a three-way race. LeMieux’s decision to abandon him may be enough to pull Crist back from the edge, or perhaps Crist will hope that the probe into state GOP spending will provide a Deus ex machina that will rescue him from humiliation in the primary. We’ll know in seven days.