He was redistricted into a more hostile seat in 2012, and the FL RINOs in the legislature saw to his defeat.
People blame Joe Walsh for losing to Tammy Suckworth, while ignoring the fact the district was redrawn to be safe RAT and NO REPUBLICAN could have won that seat now. Ain't like the GOP won it back the next election cycle and there's now a Republican winning easily in Walsh's old seat.