ATLANTA - Never have American voters re-elected a president whose work they disapprove of as much as Barack Obama's. Not that Mitt Romney can take much comfort - they've never elected a challenger they view so negatively, either.

Unless things change dramatically, this Election Day will mark a first, no matter who wins. The victor will be a sitting president with a slow economy, 8 percent-plus unemployment and an average Gallup job-approval rating below 50 percent. Or he'll be a challenger who isn't liked personally by a majority of the public and faces notable discord within his own party.

Polls since the nominating conventions show Obama slowly widening a slight lead nationally and in several key states that could decide a close election. And the mere fact that Romney hasn't ever notched a clear lead in polling, unlike previous winning challengers by this point, underscores his struggle to strike a chord with an electorate that isn't exactly enamored with the incumbent.

The presidency already gives certain campaign advantages to the Oval Office occupant, and history indicates that the longer Romney looks up at Obama, the greater the president's chances at a second term.

History, of course, isn't predictive. But it does provide context to help understand the current state of the race.

Some Republicans point to 1980 as hope for a Romney rebound. That year, Ronald Reagan pulled away from President Jimmy Carter in late October to win in a landslide that has reached almost mythical status in GOP annals. But there are many reasons why this is not 1980, not the least of which are that Romney is not Reagan and Obama is not Carter.

From Labor Day through late October, Carter was tied with or led Reagan. But, unlike Romney, Reagan had led for most of the summer, and Carter hadn't polled better than 41 percent since the spring, well below Obama's lowest head-to-head numbers this year.

Many Republicans, meanwhile, are growing restless following Romney's lackluster convention, his comments on Middle East unrest and the release of a secretly recorded video that showed the GOP nominee dismissing 47 percent of the country as believing they are "victims" and dependent on handouts.

Still, says Republican Sen. Lindsey Graham of South Carolina, "This is our election to lose. If Obama wins, he'll be rewriting political history."

Using historical Gallup job approval ratings in election years - in September where possible - Obama ranks below the seven presidents who have been re-elected since 1948. But he is in a stronger position than the three - Carter, Gerald Ford and George H.W. Bush - who lost. The three losing presidents all had unemployment rates lower than today's, but the overall economic circumstances vary.

Obama's personal favorability ratings have consistently been higher than his job approval ratings. Republican strategist Timmy Teepell, who manages gubernatorial, House and Senate campaigns for the GOP, credits independents with the difference. "They may not like what he's done," he said, "but they think he's a good guy and he's trying hard."

Voters with negative impressions of Romney, meanwhile, have outnumbered those with favorable impressions for much of his bid. That dynamic was fueled in no small part by a crowded primary field that hammered Romney on everything from his moderate record as Massachusetts governor to his business ventures at Bain Capital.

At Romney headquarters, the official line is optimism. Top pollster Neil Newhouse proffers the Politics 101 method for beating an incumbent. At the same time, he acknowledges that Romney's effort so far isn't enough.

"We recognize that over the next seven weeks we need to not just make the case why Barack Obama doesn't deserve a second term," Newhouse said, "but also to paint a picture of how a Mitt Romney presidency would be different and better."

With Romney working on the second part of that effort, the president has capsized the usual rules of an incumbent election and, in some respects, made Nov. 6 a referendum on Romney in addition to one on Obama's first term.

"We've just done a better job telling the president's story than they've done telling theirs," claims Paul Begala, a veteran Democratic strategist who is advising the pro-Obama Super PAC Priorities USA Action.

As they did at their convention in Charlotte, N.C., Democrats inside and close to the campaign say the president and his surrogates will continue to frame the last four years as progress, acknowledge that millions of Americans are still struggling and work to convince them that the groundwork for an economic renaissance is in place. At the same time, they will keep criticizing Romney as unable to understand the day-to-day concerns of middle class households.

Romney will keep contending, as he did Monday while campaigning in Pueblo, Colo., that that's exactly backward. Obama loves government and wants higher taxes, Romney says, hurting rather than helping the middle class and keeping American business from creating the new jobs that everyone claims to desire.

And, Romney said, taking a shot at Obama's dealings with foreign troubles, U.S. foreign policy should not be conducted "at the mercy of events" overseas."

Ed Meese, Reagan's 1980 campaign chief of staff who would become attorney general, said recently that his boss ran a thematic campaign "against the welfare state and an accomodationist foreign policy." Reagan held up Carter as an embodiment of larger problems, Meese said, and convinced voters he could solve them.

Begala, who worked for Bill Clinton when the Arkansas governor unseated George H. W. Bush, recalled the buzz phrase of 1992: "It's the economy, stupid." The expression took off after being captured in a picture of a dry-erase board at a Clinton campaign office. "The reason we put that sign up wasn't for voters, it was for staff," Begala said. "That sign actually said, look, this race is about three things: real change vs. more of the same, it's the economy stupid, and don't forget health care."'

Clinton led Bush from mid-summer through Election Day, regardless of whether independent Ross Perot was included as a choice. Begala said the campaign "knew it was over" the week after Labor Day.

Meese said the Reagan team wasn't confident of victory until the "weekend before the election."

Reagan pulled away after a single debate, held Oct. 27, a week before the election. Carter, Meese said, had "portrayed Reagan as this dangerous gunslinger from the West," successfully pulling Reagan down in the polls. But standing side-by-side with the president for 90 minutes, Reagan shattered that view and surged to a landslide win.

But with Carter pulling 41 percent of the vote, equal to his high heading into the meat of the campaign, the returns proved that the fundamentals of the race had never really changed: A clear majority of the electorate was always poised to fire the incumbent, who spent much of the election year dealing with a weak economy at home and the Iranian hostage crisis overseas.

Four years before Carter lost to Reagan, he won the popular vote over Ford by 2 percentage points, but he led from the start and ran his advantage in opinion polls to as much as 62-29 in the summer.

Even a few losing challengers have managed to seize the leads that have eluded Romney.

Republican Thomas Dewey led for almost the entire race before President Harry Truman pulled his memorable upset in 1948. John Kerry, another Massachusetts nominee, managed a few short-lived but clear leads over George W. Bush in 2004.

Begala said the 2004 race is perhaps the best historical example for Obama. Bush, whose Gallup job approval rating hovered around 50 percent for much of the year, controlled a tight race and was re-elected by the slimmest margin of any winning incumbent in American history.

Meese said Romney could benefit from three October appearances alongside Obama. But he also noted an important distinction: Campaigns weren't as long and as public 32 years ago.

"Ronald Reagan came into the fall much less known than Romney" is now, Meese said.

Associated Press writer Donna Cassata contributed from Washington.