One week into the general election, the polls show a dead heat. But many presidential scholars doubt that John McCain stands much of a chance, if any.

Historians belonging to both parties offered a litany of historical comparisons that give little hope to the Republican. Several saw Barack Obama’s prospects as the most promising for a Democrat since Roosevelt trounced Hoover in 1932.

“This should be an overwhelming Democratic victory,” said Allan Lichtman, an American University presidential historian who ran in a Maryland Democratic senatorial primary in 2006. Lichtman, whose forecasting model has correctly predicted the last six presidential popular vote winners, predicts that this year, “Republicans face what have always been insurmountable historical odds.” His system gives McCain a score on par with Jimmy Carter’s in 1980.

“McCain shouldn’t win it,” said presidential historian Joan Hoff, a professor at Montana State University and former president of the Center for the Study of the Presidency. She compared McCain’s prospects to those of Hubert Humphrey, whose 1968 loss to Richard Nixon resulted in large part from the unpopularity of sitting Democratic president Lyndon Johnson.

“It is one of the worst political environments for the party in power since World War II,” added Alan Abramowitz, a professor of public opinion and the presidency at Emory University. His forecasting model — which factors in gross domestic product, whether a party has completed two terms in the White House and net presidential approval rating — gives McCain about the same odds as Adlai Stevenson in 1952 and Carter in 1980 — both of whom were handily defeated in elections that returned the presidency to the previously out-of-power party. “It would be a pretty stunning upset if McCain won,” Abramowitz said.

What’s more, Republicans have held the presidency for all but 12 years since the South became solidly Republican in the realignment of 1968 — which is among the longest runs with one party dominating in American history. “These things go in cycles,” said presidential historian Robert Dallek, a professor at the University of California at Los Angeles. “The public gets tired of one approach to politics. There is always a measure of optimism in this country, so they turn to the other party.”

That desire for change also tends to manifest itself at the end of a president’s second term. "Only twice in the 20th century has a candidate from the same party as a two-term president won the presidency, most recently in 1988, when George H.W. Bush replaced the term-limited Ronald Reagan, who was about twice as popular in the last year of his presidency as President George W. Bush is now.

But the biggest obstacle in McCain’s path may be running in the same party as the most unpopular president America has had since at least the advent of modern polling. Only Harry Truman and Nixon — both of whom were dogged by unpopular wars abroad and political scandals at home — have been nearly as unpopular in their last year in office, and both men’s parties lost the presidency in the following election.

Though the Democratic-controlled Congress is nearly as unpopular as the president, Lichtman says the Democrats’ 2006 midterm wins resemble the midterm congressional gains of the out-party in 1966 and 1974, which both preceded a retaking of the White House two years later. 

One of the few bright spots historians noted is that the public generally does not view McCain as a traditional Republican. And, as Republicans frequently point out, McCain is not an incumbent. 

“Open-seat elections are somewhat different, so the referendum aspect is somewhat muted,” said James Campbell, a professor at the State University of New York at Buffalo who specializes in campaigns and elections.

“McCain would be in much better shape if Bush’s approval rating were at 45 to 50 percent,” Campbell continued. “But the history is that in-party candidates are not penalized or rewarded to the same degree as incumbents.”

Campbell still casts McCain as the underdog. But he said McCain might have more appeal to moderates than Obama if the electorate decides McCain is “center right” while Obama is “far left.” Democrats have been repeatedly undone when their nominee was viewed as too liberal, and even as polls show a rise in the number of self-identified Democrats, there has been no corresponding increase in the number of self-identified liberals.

Campbell also notes that McCain may benefit from the Democratic divisions that were on display in the primary, as Republicans did in 1968, when Democratic divisions over the war in Vietnam dogged Humphrey and helped hand Nixon victory.

Still, many historians remain extremely skeptical about McCain’s prospects. “I can’t think of an upset where the underdog faced quite the odds that McCain faces in this election,” said Sidney Milkis, a professor of presidential politics at the University of Virginia. Even "Truman didn’t face as difficult a political context as McCain.”