Ben Nelson, the moderate Nebraska Democrat, who's been discussed as a potential party-switcher in the next Congress, says he'll remain a Democrat.

He tells Roll Call's Emily Pierce:

"I'm certainly not planning to, and the answer I've been giving is 'No,'" the Nebraska Democrat said in a phone interview. When asked, he also said Republicans have not approached him as a potential switcher.

Nelson, a moderate, is up for re-election in 2012, but said Tuesday's results have not made him squeamish about running again.

The incentive for Nelson is probably diminished by the fact that, were he to join the GOP, he'd be joining the minority. If Republicans win the Washington Senate race, which has yet to be called, they'd fall two seats shy of 50. Were they to convince Sen. Joe Lieberman (I-CT) to caucus with them instead of the Democrats, that would put them at 49. Nelson would bring the total to 50. Given that the vice president casts the tie-breaking vote in the Senate, Democrats would retain control.

Nelson's only potential reason to switch would be to help his own re-election chance. Though he won re-election with 64 percent of the vote in 2006, he's taken a tremendous beating within the last year over the so-called "Cornhusker kickback," a deal to deliver federal Medicare money to Nebraska allegedly in exchange for Nelson's "yes" vote on the final bill. His approval rating dropped to 42 percent after the Senate's Christmas Eve vote on health care.

Republicans enjoy a significant registration advantage in Nebraska, as 48 percent are registered Republican, 33 percent Democratic, and 17 independent.  So becoming a Republican could help Nelson in theory.