So far as I can tell, nobody in the history of modern polling has won a presidential election from as big a hole as John McCain now stands in, at last check a national polling advantage in the neighborhood of 5 points for Obama. Now, if you are a betting man, surely you like your odds on Obama. But does that mean that the race is over? Perhaps, but not necessarily. While the circumstances are of course different, we have seen two past Republican campaigns, neither of them headed by the most dynamic of campaigners, provide examples of strong closing-month performances.

The most obvious recent example was 1996. The Gallup poll, which admittedly is one of the more volatile polls (Obama presently leads it by 8) on October 6/7, 1996 showed Bill Clinton with a commanding 22 point lead, 56-34 over Bob Dole with 5 points for Ross Perot (the first of two debates was on October 6). Four days later, after the first debate and the Vice Presidential debate, that lead was 57-34 (Clinton +23). In an October 14-15 poll, conducted on the eve of the second, October 16 debate, Dole pulled much closer (48-39, Clinton +9), but as late as October 20-21 the poll showed Clinton up 19, 52-33 with 8 for Perot. Dole then began his serious charge, pulling above 40% for the first time on November 4-5, to finish at Clinton +11 (52-41-7), and ended up at Clinton +8 on Election Day, 49-41. Dole thus ended up shaving as much as 15 points off Clinton’s lead in less than a month.

Then there’s 1976. Jimmy Carter had, of course, famously led by 34 in one midsummer poll…in a poll conducted September 24-27 (the first debate was September 23), Carter led 51-40 (+11), but in one conducted September 27-October 4, that lead dropped to +2, 47-45. Carter widened his lead to +6 on October 8-11 after the famous “Democrat wars” gaffe by Bob Dole in the October 6 VP debate, led +6 (47-41) on October 15-18 (the second debate, with Ford’s Poland gaffe, was October 15), was still at +5 on October 22-25 (the third debate was October 22), but an October 28-30 poll for the first time showed a Ford lead, 47-46. On Election Day, Carter won 50-48.

Polling today is more sophisticated, of course, and there are other distinguishing factors as well. On the one hand, the 1996 election had a third party candidate who surged up to double digits in late October, and Dole was running so far behind a still-strong GOP Congressional brand (Republicans held both Houses of Congress through that race) that a good deal of his late surge was just natural Republicans coming home. Some of the same was true of Ford’s surge. On the other hand, the 1996 race should have been much less volatile than this one – it matched a 3-decade Senate veteran with a sitting president in a time of peace and prosperity – yet the polls showed significant movement late in the game. 1976 was more similar to the present race, as it pitted a moderate Republican running in a time when the GOP brand was as destitute as it has been since the New Deal, matched against a relatively green and unknown opponent. And of course, this year’s race involves not only an unprecedentedly inexperienced and far-left presidential candidate and times of economic uncertainty and foreign war but also the triple complicating factors of no incumbent, Obama’s race, and McCain’s age coupled with Palin being not a whole lot more experienced than Obama. Those are all reasons why we might expect more, rather than less, real underlying volatility in voter preferences in addition to the possibility that the polls themselves are having trouble measuring the race. And at the end of the day, while it may at first glance seem harder to push upward in the polls against the headwind of a bandwagon once the media has (correctly) called the race for the frontrunner, as in 1996, there is a difference in the degree of difficulty between pulling up close to 50 and breaking through it.

Again: none of this should be reason for Republicans to celebrate – as I said, nobody in a hole like this has actually won a race. But history tells us that voter preferences can still shift in the last month, and if Obama’s lead now is accurately reflected by the RCP average of +5.3, it is still very much worthwhile for McCain-Palin and their supporters to fight on to the end.