Republicans like Newt Gingrich and Michele Bachmann routinely refer to Barack Obama as a one-term President these days, but that usually presumes that Obama will get defeated in a 2012 general election.  NPR wonders if Obama will actually get the nomination.  In a piece from earlier this week, NPR reviews the potential opponents that Obama may have to face, starting next year:

OK, OK. Of course it’s not going to happen. No Democrat in his or her right mind would contemplate challenging President Obama in 2012.

In fact, when the Democratic National Committee issued a press release this month announcing the date for the party’s national convention, DNC Chairman Tim Kaine emphasized — twice — that the Democrats fully intend to renominate President Obama and Vice President Biden.

But despite the obvious long odds, anything is possible in American politics. There are historical examples of tough intraparty challenges to incumbent presidents. …

Suppose: The Republicans win big in 2010. The situation in Afghanistan totally melts down. Another horrific housing crisis arises. Unemployment hits double digits. Energy prices skyrocket. Obama can’t push any more major legislation through Congress. Or pick any one of these. Epic panic sets in. And every news home page looks like the Drudge Report.

There are long odds against this, and not just because the Democrats ran Obama on the premise that he represented some sort of sea change in Washington’s corrupt machinations. The only elected President not to win his party’s nomination while actively contending for it was Franklin Pierce, a consensus choice as one of the worst presidents in American history. The others have all ascended to the office through the death of his predecessor, such as Chester Arthur and Millard Fillmore.

Political parties put a lot of effort into building the brand of incumbent presidents, especially in the modern communications age. That’s not an investment that party establishments will casually toss aside. The last serious challenge to an elected incumbent’s nomination was 1980, when a disastrous term by Jimmy Carter (another consensus choice for one of the worst presidents ever) encouraged Ted Kennedy to make his one and only serious bid for the White House. It might have succeeded, too, if it weren’t for an embarrassing interview where Kennedy couldn’t explain why he wanted to be President.

With Obama’s poll numbers collapsing already, a scenario could arise where a serious challenger may see a primary fight as the only way to rescue the party from certain defeat. But who would that challenger be? NPR goes through several candidates, such as Hillary Clinton, Howard Dean, Dennis Kucinich, Mike Bloomberg, and “other.” Of these, the only serious candidate would be Hillary, whose loss to Obama in the 2008 primaries stunned observers. Kucinich will almost certainly run and very certainly flop, and Dean’s famous collapse in 2004 won’t have anyone putting their money on an intramural run against Obama.

NPR misses one obvious candidate, however: Evan Bayh. He retired rather than run for re-election, giving himself two years to strategize for a primary fight. Bayh also became an outspoken critic of the Obama/Pelosi agenda while in the Senate and argued for pulling the Democratic Party back to the center. He has both executive and legislative experience and hails from a part of the country that Obama has seriously disillusioned, the Coal/Rust Belt. While Hillary has the taint of serving in Obama’s administration, Bayh has enough distance to have credibility as an outsider.

It’s still unlikely that Obama wouldn’t win a primary fight against Bayh or Hillary. But at least in Bayh’s case, it’s not at all unlikely that he’ll have to have that primary fight.