Charlie Crist, the sitting Governor of Florida is in the senate primary race of his life against up-and-comer Marco Rubio. 538 has some excellent analysis on his options from here on it. They suggest his best chance to win is to run for the Senate as an independant candidate, disavowing party polarization and the crazy right wing:
Probability of success. Decent; two polls have tested this and found, essentially, a three-way tie between Crist, Rubio and Meek. There are some additional structural disadvantages that Crist would face: it's tougher to raise money as an independent, for instance. Some bad narrative might also develop around the fact that he was a flip-flopper and/or that he had backed down from Rubio. If I were advising Crist, I’d tell him to really embrace the independent label if he made the switch: do a lot of TV, criticize the polarization in the country, criticize the extremism in the Republican Party, say you won’t caucus with either party if you get elected to the Senate, etc. etc. This would be a message mostly targeted to center-left voters, which is where the swing votes would be in a three-way election since Rubio would still presumably clean up with Republicans.
Big swing state: Check. Opportunity in the Center: Check. Established politician with record of success: check. Charlie has a chance to make a big splash on the national stage, setting up an independent run at the presidency. Best of all, it’s might actually happen because it might just be his best shot. He’s not the perfect candidate, but who is?