Mitt Romney crossed four time zones in the United States on Wednesday, even as President Obama pulled an all-nighter, calling supporters from Air Force One as he flew from rally to rally to rally in a 48-hour blitz.
That kind of all-out effort might be necessary in these final weeks of the race, and it's probably good public relations for the candidates as they seek to prove they can handle whatever the White House throws at them.
But there's a danger, too, and the aides to Mr. Romney and Mr. Obama know it.
Wall-to-wall campaigning eventually leads to an exhausted candidate, and that can lead to sloppiness, mistakes and gaffes.
The ramifications of a last-minute slip-of-the-tongue was already high decades ago, when candidates were first adjusting to campaigning in a television age.
But now, in the hyper-speed politics of the Internet era, the stakes are even higher if a candidate flubs a fact or seems off his game heading down the stretch toward Election Day.
Even worse for the bone-tired candidates, Election Day has become election month. There used to be time for campaign fixers to try to repair the damage from an unfortunate comment before voters entered the booth. Now, millions are already voting across the most important battleground states.
And the expectations are, if anything, even higher for candidates not to let their exhaustion show.
It's not enough to look good for the networks at 6 p.m. anymore. There are cellphone cameras everywhere, and 24-hour cable channels are broadcasting super-sharp, high-definition images that will show dark bags under the eyes if they are there.
Each of the current candidates has had his share of gaffes on the campaign trail over the years. Some have proved politically difficult.
But none would be as consequential as a mistake in the last two weeks of a presidential campaign that looks like it might be as close as a ny in recent history. Even a minor slipup could cost Mr. Romney or Mr. Obama the presidency.
The candidates - and their advisers - probably don't need a reminder of exhaustion-related gaffes that they and their predecessors have made.
But here it is, anyway:
* Senator John Kerry must have been tired the day in August of 2004 that he mistakenly called Lambeau Field (the home of the Green Bay Packers) Lambert Field, an airport in St. Louis. He was in Wisconsin at the time, campaigning hard against President George W. Bush.
* In May 2008, at the height of his battle with Hillary Rodham Clinton, Mr. Obama said he was proud to have campaigned in 57 states. There are only 50, of course.
* George Romney, Mr. Romney's father, was at the end of a hectic day of campaigning for the Republican nomination in 1967 when he told an interviewer he had been âbrainwashedâ on a foreign trip. He did not win the nomination.
* Gov. Howard Dean of Vermont was tired - but wired - when he screamed a wild âyee hawâ after losing the Iowa caucuses in 2004. His campaign never really recovered from the moment.
* The grueling 1976 election was just winding down when Jimmy Carter sat down for an interview with Playboy Magazine. (Playboy!) In the interview, he allows that âI've looked on a lot of women with lust,â but he won the presidency anyway.
* And of course, Mr. Romney has made a few gaffes, probably induced in part by being tired. Jet lag and exhaustion may have had something to do with his managing to insult the city of London on the eve of the Olympics.
How damaging are such mistakes, really?
It varies, of course. Some mistakes or gaffes could end a candidacy or even a political career. Others might have a more limited effect. But all of them steal the one thing that no campaign can afford to lose in the final days of a closely-contested election: time.
Will the current candidates manage to a void similar moments as they close out the final dozen days of the 2012 presidential campaign.
Their aides have their fingers crossed.
Follow Michael D. Shear on Twitter at @shearm.