It’s Giuliani by twenty points in the race for the GOP nomination.

The latest Rasmussen Reports national telephone poll finds former New York City Mayor Rudy Giuliani (R) with support from 35% of those likely to vote in a Republican Primary. That’s up two points from a week ago. Over the past six weeks, Giuliani’s support has ranged from 32% to 37%. 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.

Arizona Senator John McCain (R), now trails Giuliani by twenty percentage points. For the second straight week, the Rasmussen Reports poll measured McCain’s support at just 15%. That’s the lowest level of support measured so far for the man who began the campaign season as the presumed frontrunner. For the full month of March, McCain’s support has averaged just 16%, down from 18% in February and 21% in January. In general election match-ups, McCain is essentially even with Clinton, Obama, and Edwards while leading Richardson and Biden.

Eleven percent (11%) now support former House Speaker Newt Gingrich (R). However, a separate survey found that 50% of all Americans voters would definitely vote against Gingrich if he is on the general election ballot.

Eight percent (8%) prefer former Massachusetts Governor Mitt Romney (R). No other Republican attracts more than 3% support at this time. Romney trails Clinton, Obama, and Edwards. Other GOP hopefuls also trail Democrats in General Election polling.

Former Tennessee Senator Fred Thompson (R) recently indicated his possible interest in the race. Thompson has not been included in the polling to date, but will be included in next week’s update. A poll released last week showed Thompson tied with New York Senator Hillary Clinton (D) but trailing Illinois Senator Barack Obama.

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

The current survey is based upon national telephone interviews with 608 Likely Republican Primary Voters conducted March 19-22, 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.