Crist can't win the primary, but does he think he can win a three-way race as an Independent? Supposedly this upcoming move is why some in the campaign staff quit recently. If so, is it better for the Governor to make this announcement before or after he loses the primary? A bitter, mud-slinging general election between these two could propel the Democrats into the open Senate seat. However, Democrats could just as easily decide to back Crist in November for fear of Rubio.
Nate Silver looks at Crist's options.
Public Policy' Polling's numbers on a three-way race.
Running for Senate was a terrible idea in the first place, even when Crist was a shoe-in for the nomination. There wasn't much to gain. The GOP already held the seat (in a 40-member minority) and Crist hadn't shown major national ambitions. Governors run for Senate all the time - when they come from a small state and seek a larger profile. It works the other way, too, when senators want to be big state governors (of course, not in every case: see Sen. Hutchison).