McCain had tried to overcome sliding poll numbers by aggressively attacking the Illinois senator, but the Washington Post/ABC News poll indicates that the pit-bull style may have worked against McCain and Palin.
It found that 59 percent accused McCain of negative campaigning, while 35 percent said McCain is addressing the issues.
"I think we're headed for a very big win," Sen. Hillary Clinton, D-N.Y., told "Good Morning America" today.
Republicans Worry as McCain Aims for Comeback
Republicans are showing signs of worry about the state of the presidential race.
Conservative Republican William Kristol wrote in The New York Times that the McCain campaign is "close to being out-and-out dysfunctional."
"If the race continues over the next three weeks to be a conventional one, McCain is doomed," Kristol said.
McCain, speaking today in Virginia Beach, Va., acknowledged his campaign was trailing, but denied the race was over.
"The national media has written us off. Sen. Obama is measuring the drapes," he said to a cheering throng. He added, " My friends, we've got them just where we want them."
Alluding ostensibly to the country's economy, his experience as a POW, and his political fortunes, he said, "I know what fear feels like. I know what hopelessness feels like. ... I felt those things once before. I will never let them in again. I'm an American. And I choose to fight."
"Nothing is inevitable here," McCain said. "We never give up. We never quit. We never hide from history. We make history."
The Arizona senator and Palin changed their tactics over this weekend, toning down their rhetoric and insisting to their supporters that they will battle Obama but with "respect."
At a rally in St. Clairsville, Ohio, Sunday night, Palin dropped her usual references to Obama "palling around" with terrorists and didn't mention Obama's acquaintance with former 1960s radical Bill Ayers.
That reference has prompted supporters in the last week to angrily shout out things like "traitor" and "off with his head."
Instead, the Alaska governor attacked Obama for his abortion-rights stance saying, "It's not negative and it's not mean-spirited in a campaign for me to ask you to check out our opponent's record."
At another point, Palin told the crowd, "I'm not being negative, not mean-spirited, but please check out his record on partial-birth abortion and on the Child Born-Alive Act, and I'll let you judge for yourself."
Hillary Clinton Predicts 'Big' Obama Win, 'Appreciates' McCain's Efforts to Calm Race
Clinton, speaking on "GMA," noted McCain's efforts to tone down the anger among his supporters.
"I think they've been negative, but I think Sen. McCain himself has publicly said that's not the direction he wants to go, and I appreciate that," she said.
McCain has made appeals to his audiences in recent days that they confront Obama's candidacy with respect, arguing that Obama is a "decent family man."
For McCain to win next month, he will have to do what no other presidential candidate has ever done -- come back from a 10-point deficit with only three weeks to go.
"No candidate has ever lost with a lead like this since modern polling began in 1936," ABC News' senior Washington correspondent George Stephanopoulos told "GMA."
Stephanopoulos said Obama's candidacy is riding a surge of public opinion, fueled by the current economic crisis, which is devastating for the Republicans.
A record number 90 percent of Americans feel the country is on the wrong track and 73 percent disapprove of President Bush's performance, according to the ABC/Post poll.
That disapproval number is also a record, and because Bush is a Republican, it makes it harder for McCain, the GOP candidate, to argue that he would be best to handle the economy.
Obama Hammers Economy as McCain Looks for Comeback
Obama intends to bolster his economic credentials by making a major address spelling out his economic rescue plan to kick off the campaign week.
Obama has also fared better in the debates.
More Americans, 32 percent, felt better about Obama after the first two debates. Only 12 percent had a better opinion of McCain after the first two debates.
The third and final showdown will be held Wednesday.
"It's McCain's last chance," Stephanopoulos said.
"McCain may be tempted in the last debate to go hard on the attack, but that could end up hurting him more than helping him in this environment," Stephanopoulos said.
McCain has surprised his critics before. He was counted out in the Republican primaries, only to come back and win the party's nomination.
"This is a tough campaign," McCain told ABC News' Charlie Gibson in an exclusive interview last week. "I'm the underdog. I've always been the underdog from the beginning."
ABC News' Kate Snow contributed to this report.