Of course. But if she wins the nomination, she wins the Presidency. If she loses the nomination and we’re stuck with yet another RINO in the general, then say hello to Obama’s second term.
I actually think that Obama's future (like all incumbents) has almost nothing to do with whom is opponent may or may not be, and everything to do with how the country is doing, and specifically the economy.
If unemployment is above 7% or so, Obama is toast regardless of who the GOP nominee is. The Republicans could put Daffy Duck on the ticket, and still win in a landslide.
If, unemployment is less than 5%, and we don't get hit again (by Al Quaeda, NK or Iran), then Obama will stroll comfortably to reelection, probably by a margin victory as great or greater than his first.