Oct. 31 (Bloomberg) -- Republican presidential candidate John McCain goes into the campaign's final weekend a bigger underdog than any victorious candidate in a modern election.

With four days until Election Day, national polls show his Democratic rival Barack Obama leading by an average of 6 percentage points, and battleground polls show Obama ahead in more than enough states to win the decisive 270 Electoral College votes.

``There will not be a comeback curmudgeon by the name of John McCain,'' Kenneth Duberstein, who served as a chief of staff for President Ronald Reagan, said on Bloomberg Television's ``Conversations with Judy Woodruff,'' which will air later today. ``I think it's going to be Barack Obama. And I think it is going to be somewhere between 320 and 350 electoral votes.''

McCain ``is as desperate as a candidate can be,'' said Stu Rothenberg, editor of the nonpartisan Rothenberg Political Report in Washington. ``Less than five days to go and McCain's trailing in half a dozen states of which he can't afford to lose any: Nevada, Florida, Ohio, Colorado, Virginia and North Carolina.''

Illinois Senator Obama yesterday highlighted new government figures showing the sharpest contraction of the economy since 2001, a harbinger of what could be the worst recession since 1981-82. Arizona Senator McCain, meanwhile, was mum on the latest economic news showing the gross domestic product shrank at a 0.3 percent pace from July to September.

`Final Nail'

Those latest figures are ``the final nail in McCain's coffin,'' said Larry Sabato, director of the Center for Politics at the University of Virginia in Charlottesville.

To be sure, surprise events in the final days of the last two elections swayed those races. In 2000, a drunk-driving report on Republican George W. Bush, who had been leading in polls by a few points, may have cost him the popular vote. A taped message from al-Qaeda leader Osama bin Laden four years later -- when Democrat John Kerry and Bush were running about even -- likely cinched Bush's re-election.

Yet in both cases, the spread in the polls wasn't as wide as it is between McCain, 72, and Obama, 47, who also has enjoyed a threefold cash advantage.

Economic Data

Since the Wall Street crisis erupted in September, surveys show public anger about the $700 billion government bailout, the credit crunch, mortgage meltdown and high gas prices has pushed voters toward the Democrat. Obama seized on the latest figures yesterday before a crowd estimated at 13,000 in Sarasota, Florida, long a Republican stronghold.

``Our failing GDP is a direct result of a failed economic theory, of eight years of the trickle-down, Wall-Street-first, Main-Street-last policies that have driven our economy into a ditch,'' he said. ``If you want to know where Senator McCain will drive this economy, just look in the rearview mirror.''

McCain's campaign issued a statement that with the economy shrinking, ``Obama's ideologically driven plans to redistribute income will impose higher taxes on families, small businesses, and investors.''

The candidate himself didn't refer to the economic data at four rallies in Ohio, including one in Defiance, where a few thousand people braved sub-freezing temperatures.

The contenders' travel plans for the final days tell a lot about the state of the race. Obama spent yesterday in Florida, Virginia and Missouri, three states that have gone Republican in the last two elections.

Battleground States

Today and tomorrow, he is scheduled to visit four more states that voted Republican last time, and where he is polling either ahead or even: Iowa, Indiana, Nevada and Colorado. On Nov. 2 and 3, he is expected to hit two battleground states, Ohio and Florida, as well as Virginia and North Carolina, which haven't supported a Democrat for president in decades.

Obama will start airing ads in the final days of the election in McCain's home state of Arizona as well as in North Dakota and Georgia, campaign manager David Plouffe told reporters today.

Rick Davis, McCain's campaign manager, said today the candidate and the Republican National Committee would outspend Obama and the Democratic National Committee by $10 million on TV advertising in the final days.

McCain's advisers said he would likely travel from Ohio to Virginia, Florida, New Hampshire and Pennsylvania before Election Day, and possibly a Rocky Mountain state, many of which voted for Bush in 2004. McCain is also scheduled to appear on NBC's ``Saturday Night Live'' program in New York, and barnstorm through seven states on Nov. 3.

McCain's Indiana Troubles

A vivid illustration of McCain's troubles is Indiana, historically the first state to go ``red'' on network maps on Election Night, because its polls are among the first to close. Indiana hasn't voted for a Democratic presidential candidate since 1964, yet the latest polls from the Indianapolis Star and a local television station show Obama either tied or slightly ahead.

Indiana is the most manufacturing-dependent state in the nation, and ``the Bush economy has not been kind to Indiana,'' said state Democratic Party chairman Dan Parker. The state lost 110,000 manufacturing jobs under Bush, and that has hurt the Republican brand, he said.

Obama in Indiana

The Obama campaign has 44 field offices and more than 200 paid organizers in Indiana. The McCain campaign is working out of the state Republican Party's county offices, and is relying heavily on dedicated volunteers, said Republican state party chairman Murray Clark, citing nearly 150,000 calls made by volunteers this week.

``It's quite competitive,'' Clark said. Obama ``has been here since March, he's developed an independent campaign structure, and he has unlimited resources. Comparing their visits is a legitimate way to look at it.''

By today, Obama will have visited Indiana nine times in the general election, and 48 times this year, including the primary. McCain, who didn't have a contested primary in the state, visited twice before the general election and hasn't returned since July. His campaign sent his running mate, Alaska Governor Sarah Palin, to Indiana three times in the last two weeks.

In Florida, the Republican Party chairman, Jim Greer, said ``Obama has really focused on a lot of things that typically in the past Democrats haven't focused on: the amount of energy, the amount of time, the places they've campaigned.''

Republican Optimism

Still, Greer predicted McCain would squeak out a win in the state, despite polls showing Obama 3.5 percentage points up on average.

``At McCain events, although smaller -- there's no doubt about it -- there seems to be a stronger commitment,'' he said.

That won't be enough, Rothenberg said. For all the talk ``in Republican circles about McCain on the march, McCain making a comeback, there's precious little evidence he can get to 270 electoral votes,'' he said.

Rothenberg said a McCain upset would be akin to the 1948 election, where President Harry S Truman was elected after trailing in polls to New York Governor Thomas Dewey. Unlike now, polls that year ended more than a week before voting, failing to catch a final surge for Truman.

``If John McCain were to win, it would be a stunning, dramatic reversal comparable to Dewey and Truman, but that would take a historic, dramatic turnaround,'' he said.

To contact the reporter on this story: Indira Lakshmanan in Washington at ilakshmanan@bloomberg.net.

Last Updated: October 31, 2008 14:13 EDT