Several post-election polls have shown Sarah Palin as the Presidential nominee of choice for Republicans in 2012, but a new national survey from Public Policy Polling suggests that such a contest would result in the largest popular vote blowout since George McGovern ran against Richard Nixon in 1972.

Obama leads Palin 55-35 in the hypothetical contest. He has an 89-7 advantage among Democrats. Among Republican he trails 66-17. Last year exit polls showed Obama winning only 9 percent of the Republican vote, so it appears Palin would lose a lot more voters within her party than McCain did.

It’s also worth noting that while only 3 percent of Democrats are undecided about who they would support in an Obama/Palin contest, 18 percent of Republicans are, an indication of even more hesitation with some GOP voters about supporting Palin if she ended up as the nominee.

“It’s impossible to say what twists and turns the American political landscape will see between now and 2012,” said Dean Debnam, President of Public Policy Polling. “What is clear is that four months ago John McCain lost to Barack Obama by seven points nationally, and at this point in time Sarah Palin trails Obama by a much greater 20-point margin. Obama would easily win more than 400 electoral votes in a contest against Palin at this point in time.”

Obama’s overall national approval rating is 55 percent, with 37 percent of voters disapproving of his job performance. 50 percent of Americans have an unfavorable opinion of Sarah Palin, with 41 percent holding a positive view of her.

PPP conducted a national survey of 691 voters from March 13th-15th. The survey’s margin of error is /-3.7 percent. Other factors, such as refusal to be interviewed and weighting, may introduce additional error that is more difficult to quantify. Complete results can be found at www.publicpolicypolling.com.