Americans are pretty evenly divided on whether they'd rather have four more years of Barack Obama or replace him with a Republican in 2012, with 48% going for Obama and 47% with a generic Republican. But with the exception of Mitt Romney none of the actual top tier Republican candidates poll as well against the President as the hypothetical one.
Obama leads Romney 47-46, matching his generic ballot lead. Obama's lead expands to 48-45 over Mike Huckabee, 49-43 over Newt Gingrich, 51-42 over Sarah Palin, and 48-37 over Marco Rubio who PPP followers voted in as this month's 'wild card' candidate [Tom Jensen, "Obama Leads All Republicans," Public Policy Polling, 2010.11.29].
PPP also finds that Palin, the Celebritarian playing the press better than any regular Republican, is viewed as electable by only 28% of Americans. She can't even get a majority of Republicans to say they think she could beat the President in 2012.
One-term President? Go ahead, conservatives. Keep telling yourselves that, if it makes you happy. But you have yet to come up with someone who can make that happen.