Sen. Trent Lott, R-Miss., is casting doubt on the chances of any U.S. senator – including Hillary Clinton and Bill Frist – of winning the White House in 2008.

"I don't think any senator can win the nomination," Lott told the Hill, a newspaper covering congressional issues. "If they get the nomination, they won't be elected president."

He suggested the only way a senator would become the next president would be if both major parties nominate a senator.

"I don't think senators make good candidates, actually, because of what we do. If you're in the Senate for 10 or 15 years, there's a good chance you've voted on both sides of every issue."

He says it's that scenario which hampered Sen. John Kerry in his battle against President Bush last year, as Kerry became portrayed in television commercials as a political flip-flopper for seemingly taking stands both for and against certain issues.

Lott said governors like Mitt Romney of Massachusetts and even Haley Barbour of Mississippi could secure the Republican nomination.

His comments come at a time when a large number of Republican senators are said to be interested in a presidential bid three years from now. Among them: Bill Frist of Tennessee, John McCain of Arizona, Rick Santorum of Pennsylvania, Chuck Hagel of Nebraska, and Sam Brownback of Kansas.

On the Democratic side, New York's Hillary Clinton has been mentioned as a potential candidate.

According to the latest reading of the "Hillary Meter" by Rasmussen Reports, 47 percent of Americans now believe Mrs. Clinton is politically liberal – up from 43 percent two weeks ago, but down from 51 percent in late January.

Thirty percent of voters say they'd definitely vote for Hillary if she runs in 2008. Forty percent would definitely vote against her.