With the two political conventions now over, Election 2012 turns to a month that could be both fallow and consequential. Fallow because the coming three weeks are the prelude to October and the presidential and vice presidential debates that could be more decisive than in the past. Consequential because the candidate who has led in mid-September generally has gone on to win in November.

Republican nominee Mitt Romney got no significant bounce from his convention in Tampa. Preliminary indications suggest that President Obama may have done better, although it will take more evidence to know whether it’s real or lasting, given Friday’s weak jobs report.

Advisers to both candidates say they anticipate the continuation of a close race and that they’re satisfied with where they stand.

“We’re very comfortable with the reality of what this race is about, and we’re not in the momentum business,” said Stuart Stevens, Romney’s chief strategist. “We’re in the talking-to-voters-about-their-lives business.”

David Axelrod, chief strategist of the president’s reelection campaign, said conditions in the country militate against any major movement in the polls. While predicting that Obama would win a second term, he said, “I don’t think the structure of the race allows for a big breakthrough.”

History is an imperfect guide to the future, but as the presidential campaign moves into its final eight weeks, Obama and Romney may be looking to the past for inspiration and encouragement as they try to open up what has been a closely fought contest.

For Romney, that past campaign is 1980, when a challenger who happened to be a former governor struggled for months to gain the upper hand against a weakened and vulnerable incumbent, only to break open the election in the final days of the campaign.

For Obama, it may be 2004, when an embattled incumbent with approval ratings hovering below 50 percent and whose major undertaking the country had soured on managed to find a path to victory over a challenger tagged as a flip-flopper who had trouble connecting with voters.

The 1980 analogy holds for Romney the potential for a breakthrough during or after the debates. In that campaign, Ronald Reagan trailed President Jimmy Carter into the month of October. He moved ahead after the candidates’ only head-to-head debate. Romney advisers have said for months that the longer they stay roughly even with the president, the better their chances of winning in November.

Obama advisers, however, see that as a flawed analogy. The electorate was less polarized then than now, with more opportunity for each candidate to attract a larger number of undecided voters than exists today. They also note that Reagan’s image was more positive than Romney’s has been. “There are so many ways that’s not plausible,” Axelrod said of the 1980 analogy, “starting with Obama’s not Carter and Romney’s not Reagan.”

Stevens offered this rejoinder just before Friday’s jobs report. “The obvious parallel is Jimmy Carter, but when Jimmy Carter held his convention, unemployment was 7.7 percent. Now it’s 8.3 percent.”

If Obama’s team sees limitations in the 1980 comparison, Romney’s advisers question whether Obama can do this fall what President George W. Bush did eight years ago.

In that campaign, Bush’s approval ratings hovered below 50 percent throughout the year. He took a lead right after his convention in New York, fell back into a statistical tie in late October and ended up winning by three percentage points over Democratic nominee John F. Kerry.

Bush won that election despite growing dissatisfaction with the Iraq war and his leadership. He did it by firing up his base, which produced a big turnout among his loyalists, and then increasing his 2000 margins among key groups such as Latinos, suburban women and Roman Catholics. That was enough to put him over the 50 percent threshold.

Bush’s model may be similar to the strategy Obama could use to win in November. But Romney advisers say there is one major difference between 2004 and 2012: how the candidates are judged on the dominant issue in the election. Then it was who could keep the country safe. Today it’s who can fix the economy.

“Unless Kerry could win that fight [on keeping the country safe], it was always going to be very, very difficult to win,” said Russ Schriefer, a senior strategist in the Romney campaign. In this campaign, he added, “President Obama is on the wrong side of the [economic] issue.”

Romney came out of his convention having made small gains in his overall favorability rating as well as his standing overall with women, but advisers said they need to make further inroads in those areas.

The Romney team thinks their candidate survived the Obama campaign’s summer advertising onslaught, which focused negative attention on Romney’s personal finances and his record at Bain Capital, the corporate buyout and venture capital firm he founded. With both conventions finished, Romney’s advisers say the race will remain as it has for months: deadlocked.

Romney’s team sees the three presidential debates as potential game-changing moments. For the first time in the campaign, Romney will be on equal footing with the president, and his advisers see that as perhaps his biggest opportunity to take control of the race. Romney is undergoing extensive preparation for the debates, taking three days off the campaign trail last week to practice with top advisers in Vermont.

“There are going to be moments in this campaign, like October 3rd, the first presidential debate, when people hit the pause button and reconsider the candidates,” Romney pollster and strategist Neil Newhouse said. “That may not be the only moment. There may be other things that happen that cause those moments that are impossible right now to predict.”

Romney’s brain trust has long thought, however, that the race will hinge on how independent voters evaluate Obama’s handling of the economy.

Romney advisers think they have made the case that Obama’s policies have not led to a robust recovery but think they have more work to do to convince voters that Romney has a credible alternative economic plan.

“Nobody needs to be convinced really that we’re not on the right track,” said Virginia Gov. Robert F. McDonnell (R), a leading Romney surrogate. “Now it’s just bolstering the credibility of the Romney plan for the middle class, to get the independent voters understanding that this is a solid solution for bolstering the American dream for the middle class. I think that’s the closing argument.”

The Obama camp feels equally confident about its plan, particularly after the convention in Charlotte. Speeches by first lady Michelle Obama and former president Bill Clinton drew positive reviews, even from many Republican strategists. Reviews of Obama’s speech were much more mixed, with many saying it was far from his most memorable address.

Obama advisers, however, say the president’s speech accomplished virtually everything they were hoping for, both in energizing the base and in delivering the right messages and reassurances to voters still making up their minds. A senior Obama adviser said that based on the research the campaign did Thursday night, Obama’s speech received higher marks than did Romney’s a week earlier.

But the president got a fresh dose of reality Friday morning when the government reported that the economy added just 96,000 jobs in August, fewer than had been forecast. The unemployment rate ticked down from 8.3 percent to 8.1 percent, but largely because many people stopped looking for work.

Romney’s team says those numbers will be a further reminder to voters that Obama’s policies aren’t working.

Axelrod said the latest report will not create further problems for the president. “I think people are realistic about where we are,” he said. “They know we’re in a long, hard march. . . . That’s not the issue. The question is where we go from here.”

That was the focus of the past two weeks, as first Romney and then Obama made their cases about who has the plan and the values to help the middle class. The next big moment in the campaign will come on Oct. 3, when Obama and Romney meet in Denver for the first of their three debates.

But September also may help to reshape the race. The current phase has begun with new ads and a punishing pace for the candidates. Whoever can capi­tal­ize most on this post-convention period could gain an advantage before those debates begin.

As Democratic pollster Geoff Garin noted, “There’s a lot of history behind these [next] three weeks being pretty crucial.”