Former North Carolina Senator John Edwards continues to chalk up impressive margins over GOP presidential candidates in Rasmussen Reports surveys of potential Election 2008 match-ups. In the latest poll Edwards leads Senator John McCain (R) by 13 percentage points, 49% to 36%.

Over the past month, Edwards has almost doubled his margin over McCain. In May it was Edwards 48%, McCain 41%.

Edwards also crushes former Massachusetts Governor Mitt Romney (R) 51% to 33%. While still a rout, those numbers are actually a bit better for Romney than those from a month ago.

This poll is the latest in a recent series of polls showing a declining trend for the McCain campaign. The man once presumed to be the dominant frontrunner for the GOP nomination is now barely attracting double digit support.

A Rasmussen Reports analysis notes that McCain has suffered because his position on Iraq and immigration is so closely linked to that of President Bush.

Senator McCain is now viewed favorably by 48% of all voters, unfavorably by 55%. That's a jump in negative feeling since late May and another declining indicator.

McCain trails Illinois Senator Barack Obama by six points. New polling on a Clinton-McCain match-up will be released soon. Polling conducted before the immigration debate arose found McCain with a slight lead over Clinton.

Senator Edwards often does so much better among female voters than male voters that he can easily win an overall match-up despite lagging among male voters. In the current match-ups, though, neither McCain nor Romney attract more than 39% of men.

Edwards is viewed favorably by 54%, unfavorably by 38%. His favorable rating has been fairly stable since March.

Over the past eight months, Governor Romney's favorable rating has slowly grown from 30% to 36%. But his unfavorable rating has climbed from 29% to 42%.

Rasmussen Reports continuously updates general election match-ups and other measures for all Republican and Democratic Presidential candidates. Also regularly updated are favorability ratings for Members of Congress, Other Political Figures, and Journalists along with public attitudes towards Congress, the War on Terror, and other topics.

Rasmussen Reports releases updated polling data on the Democrat Nomination Process every Monday and on the Republican contest every Tuesday. Results for the Generic Congressional Ballot are updated monthly.

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