President Obama leads several top would-be Republican challengers by an even larger margin than last year, a new poll found Friday.

Obama would beat former Massachusetts Gov. Mitt Romney, former Arkansas Gov. Mike Huckabee, former Alaska Gov. Sarah Palin and former House Speaker Newt Gingrich in head-to-head match-ups if the 2012 election were held today, a new Fox News poll found.

Obama also leads all four of those candidates by healthier margins than he had in the same tests of those match-ups in late September of last year, the poll found.

Forty-eight percent of registered voters would choose Obama, versus 41 percent who would vote for Romney, the poll found. (Obama led 41-40 percent last fall.)

In a race against Huckabee, Obama would win 49-41 percent, an expanded margin from the 43-40 percent lead the president held in September.

Obama clears the 50 percent marker against both Gingrich and Palin. He would beat Palin by more than 20 points — 56 to 35 percent — and best Gingrich 55-35 percent. The president led Palin 48-35 percent last September, and was ahead of the former Speaker with 53 percent to Gingrich's 29 percent last fall.

As a bonus, the Fox poll also tests how Obama would fare against former Florida Gov. Jeb Bush (R), who said he's not running, in 2012. Fifty-four percent of registered voters would choose Obama in that match-up, compared to 34 percent who would elect Bush. 

Many of the candidates tested against Obama are doing their best to take the president down a peg during speeches at this weekend's Conservative Political Action Conference.

The poll, conducted from Feb. 7-9 by Democratic pollster Anderson Robbins Research and GOP pollster Shaw & Company Research, has a 3 percent margin of error.