Why would Nelson throw away his pretty safe Senate seat (he won his last re-election by 13)? Republicans would almost certainly pick up his seat. This is really dumb.
*please do it*
No they wouldn't. The Democrats could just run Crist or someone like Patrick Murphy. If Nelson wins, he could wait to resign and appoint a Democratic successor.
Why would Crist run as a Democrat again after his party throws him out AGAIN? That's pretty desperate, and he'd probably lose to a non-Scott Republican. Patrick Murphy has potential, but he also beat what may be the most crazy conservative running in a relatively neutral district. The Florida Republicans have strong candidates, while Florida Dems have Nelson, Crist, maybe Murphy, and then it's blank.