Obama is up, Giuliani slips to second, Edwards gains ground, and the other candidates remain in pretty much where they were a month ago. Those are the April results from a Rasmussen Reports national telephone survey asking if citizens would definitely vote for or against the 2008 contenders.

Thirty-three percent (33%) of Likely Voters say they’d definitely vote for Illinois Senator Barack Obama (D). That’s the highest total received by any of ten leading Presidential hopefuls included in the poll. Thirty-three percent (33%) also say they’d definitely vote against Obama giving him a net differential of zero (33% definitely for minus 33% definitely against equals net differential of 0). All other candidates have a net differential in negative territory meaning more people are set to definitely vote against them rather than for them. Other polling during the past month found Obama’s favorability ratings have increased to the highest level of any 2008 candidate (see summary of all Democratic and Republican candidates)

A month ago, Obama had a net differential of minus 9 (28% definitely for, 37% definitely against).

Former New York City Mayor Rudy Giuliani (R) slipped to second place in this measure of base support. Twenty-nine percent (29%) would definitely vote for him while 34% would definitely vote against. While that net differential of minus 5 is better than all other candidates except Obama, it represents a significant decline from last month when America’s Mayor sported the only net positive numbers in the field (31% definitely for, 28% definitely against, net plus 3). During the past month, Giuliani’s favorables slipped to 58%. That too is higher than all candidates except Obama but represents a decline from 71% in December. Still, Giuliani remains the frontrunner in the race for the GOP nomination.

The newest face in the race, former Tennessee Senator Fred Thompson (R), has the third best numbers overall—19% definitely for, 29% definitely against, net differential of minus 10.

Former North Carolina Senator John Edwards (D) also gained ground in April. Twenty-six percent (26%) say they’d definitely vote for him while 37% would definitely vote against. That net differential of minus 11 represents an eight-point improvement from last month and is good enough for fourth place overall. General election match-up polls now show Edwards leading all Republicans.

Opinions are most solid concerning the frontrunner for the Democratic nomination, New York Senator Hillary Clinton—78% have an opinion of whether they’ll definitely vote for or against her regardless of who she runs against. That includes 30% who would definitely vote for the former First Lady and 48% who would definitely vote against her. A month ago those figures were 30% definitely for and 46% definitely against. The 48% who would definitely vote against Clinton places her second only to former House Speaker Newt Gingrich (R) in that dubious category. Forty-nine percent (49%) would definitely vote against Gingrich.

See summary list comparing this month and last for all candidates. Rasmussen Reports also asked Americans whether they’d vote for a number of celebrity non-candidates including Colin Powell, Jon Stewart, Peyton Manning, Bill Gates, and Katie Couric. With the exception of Powell, all fared much worse than the 2008 candidates. See a summary of the results and the article.

Rasmussen Reports continuously updates favorability ratings and general election match-ups for all Democratic and Republican candidates. Also available are continuously updated ratings for Members of Congress, Other Political Figures, and Journalists and a daily update of the President’s Job Approval.

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