In the race to win the Republican Presidential nomination, former New York City Mayor Rudy Giuliani’s (R) now has his biggest lead of the season—21 percentage points. Giuliani now attracts support from 37% of those likely to vote in a Republican Primary, up from 34% a week ago. While Giuliani gained three points, Arizona Senator John McCain lost three points and now is supported by just 16% of those surveyed. That is the lowest level of support measured so far who not long ago was presumed to be the frontrunner for the nomination.

Rasmussen Reports releases updated polling data on the Republican nominating contest every Tuesday. Results for the Democrats are updated on Mondays.

Giuliani currently leads all Democrats in General Election match-ups. This includes Senator Hillary Clinton, Senator Barack Obama, former Senator John Edwards, Governor Bill Richardson, and Senator Joe Biden.

McCain is essentially even with Clinton, Obama, and Edwards while leading Richardson and Biden.

Former House Speaker Newt Gingrich (R) earned 11% support in the latest Rasmussen Reports poll. Former Massachusetts Governor Mitt Romney (R) is at 10% and no other Republican cracks the 2% barrier.

Last week was a good week for the Giuliani campaign as he exceeded expectations in straw polls conducted at the C-PAC conference and in South Carolina. McCain avoided the C-PAC convention and his name attracted boos when mentioned from the platform. This survey was completed before Gingrich publicly admitted an affair during the investigations of the Clinton-Lewinski matter.

Senator Sam Brownback (R) has not made much of a mark in the Republican primary field but is within five points of Senator Hillary Clinton (D) in a general election match-up. Other GOP hopefuls trail Democrats in General Election polling.

The current survey is based upon national telephone interviews with 598 Likely Republican Primary Voters conducted March 5-8, 2007. The margin of sampling error is +/- 4 percentage points with a 95% level of confidence.

See a summary of all match-ups along with favorability ratings and perceptions of the candidates’ ideology. A summary is also provided for Democratic contenders.