Jim Messina, President Obama’s campaign manager, spoke by conference call to more than 100 members of his Virginia staff last Sunday night to ask whether they’re meeting their door-knocking, phone-calling and voter-registering goals — and to urge them: “Now is the time to push even harder.”

The next night, the call was to Colorado. On Wednesday, he met privately with Senate Democrats on Capitol Hill to deliver a similar message. And on Saturday, he traveled to Wisconsin to meet with field organizers, neighborhood team leaders and other volunteers there.

“Ignore the polls,” Messina said on the call to Virginia, he recalled. “There are always going to be polls showing us up. There are always going to be polls showing us down. None of that matters. What matters is your voter contacts in your state.”

Messina’s sense of urgency might seem disingenuous in the current political environment. Republican Mitt Romney has lurched from one damaging moment to the next. Recent polls show him trailing Obama in pivotal states, including Ohio and Virginia. Privately, advisers say they believe they are winning — or at least on track to do so Nov. 6.

But if there is an ongoing danger for the president, it is that his supporters will take his apparent advantages for granted — and fail to show up on Election Day.

And so as Obama’s fortunes have appeared to improve, so, too, have his campaign’s efforts to convince supporters that the race is far from over. They say they have been aided by Democrats’ deep concern over Romney’s policies, lack of details and choice of running mate in Rep. Paul Ryan (Wis.). All of it has inspired Obama backers to redouble their efforts to stay engaged.

“You know what? I’m very scared about this election,” said Ann Fremgen, 59, a retired teacher from Golden, Colo., one of scores of current and former teachers sporting “Educators for Obama” shirts who listened to the president speak last week against a backdrop of Colorado’s Flatiron Range. “I would be devastated if Romney were elected. I think he is a total puppet. I am talking to people. I am here today. I have not volunteered yet, but I am going to.”

Obama’s advisers view complacency as a special threat because they have built so much of their strategy around a vast field operation to register new voters, urge them to the polls or persuade that tiny band of undecided Americans to choose Obama. The effort is entering crunch time now, with registration deadlines looming and early voting underway in a few states. But it is an effort that depends heavily on the energy and enthusiasm of thousands of field workers and volunteers across the country. Anything that could suppress that enthusiasm — like the idea that Romney is sunk — makes nerves jangle in Obama’s Chicago headquarters.

And they are facing a torrent of media coverage — and comedy routines — reinforcing the narrative that momentum favors Obama. “The Daily Show’s” Jon Stewart won’t stop talking about Clint Eastwood’s now-infamous monologue with a chair. Pundits have declared a recent Politico piece about dissent within the Romney campaign tantamount to an “obituary.” And most recently, the news and late-night shows have endlessly played a newly uncovered video clip of Romney declaring that nearly half of Americans “believe they are victims” and that “the government has a responsibility to take care of them.”

Worse for Obama, the political activists who make up his field operation pay more attention to this stuff than the electorate overall.

“Though [Romney] is melting down, over confidenceis dangerous,” Bill Burton, who leads an independent super PAC supporting Obama, said in a tweet this week. Although Burton has welcomed attention on Romney’s woes — his committee, Priorities USA, put up a TV ad within 24 hours criticizing the video remarks — he also claims to be certain that the race will remain close, and that Obama’s fortunes could turn as quickly as Romney’s seemed to.

Such urgency has been apparent in the sprawling crowds Obama has drawn to political rallies in Colorado, Ohio, Florida and Virginia in recent weeks. But it may also be at least partly the fruits of rhetorical seeds planted by the campaign and his allies.

Despite their fundraising prowess, Obama advisers have emphasized the financial advantage they expect Romney — and particularly his independent Republican supporters — to parlay into an outmatched ad war on the airwaves.

“These folks have super PACs that are writing $10 million checks and have the capacity to just bury us under the kind of advertising that we’ve never seen before,” Obama told about 200 high-dollar donors at a fundraiser at the Waldorf Astoria in New York on Tuesday night.

That messaging seems to be working — despite the emergence of more and more evidence that the Republican spending advantage is not moving the needle much in some of the most hard-fought states in the country, including North Carolina, Ohio and Virginia.

The Obama team also has been relentless in pushing out the notion of the stark choice voters face this fall — the idea that a Romney win would set the nation back, while a second term for Obama would keep the country moving ahead.

Jane Gouveia, 59, a property manager and an Obama volunteer from Lakewood, Colo., practically recited the Obama campaign’s alarmist message as she spilled out of his recent outdoor rally in Golden on a sunny September afternoon. Gouveia also said she is convinced that Democrats face an extraordinary opponent in the Romney fundraising juggernaut, a fact that has compelled her to volunteer one day a week at a local Obama office. “There’s no way we can be complacent!” she said. “The amount of money that’s being spent to distort public opinion compels me into action.”

There is an irony to the fact that Obama’s team is now worried that too much confidence could keep supporters at home when, just a few weeks ago, much of the talk was about an enthusiasm gap between the two parties. Then, pundits wondered if Democrats were unexcited enough by Obama’s leadership to stay home; now, the purported concern is that they are so sure he’ll win that their effort isn’t needed.

“If you just think of the things that happened in the last 10 days or so, there’s a lot more time for a lot more developments,” Burton said. “Another hidden tape, another foreign-policy moment, and some big moments, too, like the debates. So everything can change in a second in this race.”

Rosalind S. Helderman contributed to this report.