A fresh spate of polls released on Monday showed Democratic presidential hopeful Barack Obama pulling ahead of Republican rival John McCain, who has borne the political brunt of the US financial crisis and been hurt by a rise in unfavorable views of his running mate Sarah Palin.
With less than a month until the November 4 election, the CNN/Opinion Research Corporation poll found 53 per cent of likely voters back Obama for president, compared with 45 per cent for McCain.
CNN noted the eight-point margin doubles Obama's advantage from the four-point lead he held in the previous CNN/Opinion Research poll, conducted mid-September.
The poll suggests President George W Bush's record low approval ratings, at 24 per cent, contribute to the Republican ticket's woes.
"Bush has now tied Richard Nixon's worst rating ever, taken in a poll just before he resigned in 1975, and is only two points higher than the worst presidential approval rating in history, Harry Truman's 22 per cent mark in February 1952," said CNN Polling Director Keating Holland.
The ongoing economic turmoil is also contributing to Obama's lead.
Sixty-eight percent of likely voters are "confident in the Democratic presidential nominee's ability to handle the financial crisis, 18 points ahead of McCain, and 42 points ahead of President Bush," reported CNN.
McCain's running mate, Alaskan governor Sarah Palin, who briefly rallied the Republican base in the weeks after she was plucked from obscurity little over a month ago, appears to be falling out of favor with American voters.
Forty percent of Americans hold an unfavorable view of Palin, a 13 point jump from a month ago, and compared with just 21 per cent who an held unfavorable view in late August.
"A majority of Americans now believe that Sarah Palin would be unqualified to serve as president if it became necessary, and her unfavorable rating has doubled," Holland said.
The Gallup Institute polling firm also said Obama enjoyed a widening lead, with their daily results showing Obama with an eight point lead over McCain on Monday, in the tenth consecutive day that Obama has been ahead.
"This ten-day stretch of a significant Obama lead is the longest since he became the presumptive nominee back in early June, and the longest for either candidate at any point in the campaign," Gallup said in a statement.
In other national polls released on Monday, Obama had leads outside the margin of error in all of them.
Rasmussen found Obama to have an eight point advantage (52 per cent to 44 per cent), Diego/Hotline gave the Illinois senator a six points lead (47 per cent to 41 per cent), and GW/Battleground gave him a seven point lead (50 per cent to 43 per cent).
In a significant about-turn for Republican stronghold Virginia, a Boston-based Suffolk University poll found that Obama holds a commanding 12-point lead.
Voters in Virginia, which has consistently voted Republican since 1968, opt for Obama by 51 per cent to 39 per cent.
The "broad-based Republican hegemony is threatened,"said David Paleologos, director of policy research center of Suffolk University in Boston.
"Mr. Obama enjoys, north of the state, mobilizing voters living in the suburbs of the capital Washington, south, he has the support of blacks and across the state, young voters," said Paleologos.
The CNN/Opinion Research Corporation poll questioned 1,006 people by telephone on October 3-5, and has a sampling error of plus or minus 3.5 percentage points.
The daily Gallup survey is conducted among a sample of 2,744 people, with a sampling error of plus or minus two points.