Centrist Republican candidates thinking of running for office should "have [their] head examined," President Obama's top political strategist said Thursday.

Obama's 2008 presidential campaign manager, David Plouffe, said he expected that conservative primary voters allied with the Tea Party movement would make it all but impossible for centrist GOP candidates for Congress or president to succeed.

"This is the absolute tip of the iceberg," Plouffe said of GOP Senate candidates like Rand Paul in Kentucky or Christine O'Donnell in Delaware at a pre-election briefing for reporters.

"If you're a moderate Republican thinking of running, you need to have your head examined," he added.

Plouffe said he expected the momentum on the other side of the aisle to be with the crop of candidates more aligned with the Tea Party movement who have crept forward in Republican primary battles during the 2010. The phenomenon has been especially pronounced in Senate races, with Paul and O'Donnell's victories over more establishment candidates in primaries, along with Sharron Angle's win in Nevada, Mike Lee's win in Utah, Joe Miller's win in Alaska, and Ken Buck's win in Colorado -- all victories over establishment or incumbent Republicans.

"All the energy is going to be among Rand Paul, Christine O'Donnell types," Plouffe said. "The gate that you have to get through is going to be farther to the right."

Plouffe didn't say which Republican presidential candidates might make it through that gate, but he did hint that he didn't expect former Alaska Gov. Sarah Palin, a major backer of those Tea Party candidates, to be one of them.

"Something tells me we won't get that lucky," he said.