If the election were held today (and yes, we know it won't be), Democratic contender Sen. Hillary Rodham Clinton would get 51% of the vote to Republican candidate Sen. John McCain's 46%, the latest USA TODAY/Gallup Poll estimates. In a match-up between Democratic Sen. Barack Obama and McCain, Obama comes out ahead 49%-47%.
Both Democrats have overtaken McCain since the last USA TODAY/Gallup survey. In that Feb. 21-24 poll, McCain led Clinton 50%-46% and he led Obama 48%-47%.
Gallup surveyed 685 "likely" voters across the nation from Friday through Sunday. It says the margin of error on each result is +/- 4 percentage points. That means neither Clinton nor Obama's lead in the new poll is "outside" that margin. Clinton's support could be as low as 47% (because 51-4=47) and McCain's could be as high as 50% (because 46+4=50).
http://blogs.usatoday.com/onpolitics/2008/03/usa-todaygallup.html