NASHVILLE, Tenn. (AP) — John McCain dismissively called rival Barack Obama ‘‘that one,’’ Obama mocked McCain’s ‘‘Straight Talk Express,’’ and both left the debate stage to return to the campaign trail Wednesday.

CNN’s national poll of debate watchers found that 54 percent said Obama did the best job, compared to 30 percent who said McCain performed better. While 51 percent of those polled said they had a favorable opinion of McCain, unchanged from before the debate started, 64 percent said they had a favorable opinion of Obama, up 4 percentage points from before the debate.

By more than a 2-1 margin, 65 percent to 28 percent, more people said they found Obama more likable than McCain during the debate, according to the CNN/Opinion Research Corp. survey.

On the question of who won the debate, a CBS News/Knowledge Networks poll of uncommitted voters found a similar result. Forty percent said Obama won, 26 percent said McCain won, and 34 percent thought it was a tie.

Playing off the second debate, the Obama campaign released a TV ad Wednesday that continued the criticism that McCain’s health care plan included taxing employer-based health care benefits. ‘‘Instead of fixing health care, he wants to tax it,’’ the ad says.

McCain’s campaign, in turn, put out a TV spot contending that Obama promises nearly $1 trillion in new spending in the wake of the $700 billion financial rescue plan Congress approved. ‘‘Sound crazy? the ad asks. ‘‘It is.’’

It took just eight minutes into Tuesday’s presidential debate for Republican candidate McCain to land the first blow, blaming Obama and Democrats for the collapse of mortgage giants Freddie Mac and Fannie Mae.

‘‘They’re the ones that, with the encouragement of Sen. Obama and his cronies and his friends in Washington, that went out and made all these risky loans, gave them to people that could never afford to pay back,’’ McCain said.

Obama responded: ‘‘I’ve got to correct a little bit of Sen. McCain’s history, not surprisingly. … In fact, Sen. McCain’s campaign chairman’s firm was a lobbyist on behalf of Fannie Mae, not me.’’

McCain campaign manager Rick Davis has a stake in a Washington lobbying firm that received thousands of dollars a month from Freddie Mac until recently.

Davis is one of the many figures in both campaigns and near them who have been targeted as reasons why each should not be supported. As they head back on the road Wednesday, both campaigns say those associations would again be highlighted.

McCain running mate Sarah Palin has questioned Obama’s ties to William Ayers, who 40 years ago was a member of the Weather Underground, a radical group that claimed responsibility for a series of bombings. Obama had a limited relationship with Ayers, who lives in the same neighborhood and teaches at the University of Illinois at Chicago.

Democrats have criticized McCain for his role in a 1980s banking scandal. He was one of five senators who had accepted contributions from Charles Keating Jr., a real estate speculator and savings and loan owner. Keating’s institution failed and cost many investors in uninsured financial products their life savings.

Neither figure came up during Tuesday’s debate. Nor did either candidate call the other a liar, a familiar charge in this contentious campaign.

The closest: ‘‘You know, Sen. McCain, I think the Straight Talk Express lost a wheel on that one,’’ Obama said.

During a discussion of an energy bill McCain offered up a two-word phrase that drew a quick reaction from the Obama campaign.

‘‘You know who voted for it? You might never know. That one,’’ McCain said, pointing at his opponent.

Obama campaign manager David Plouffe said after the debate, ‘‘John McCain was all over the map on the issues, and he is so angry about the state of his campaign that he referred to Barack Obama as ’that one’ — last time he couldn’t look at Sen. Obama, this time he couldn’t say his name.’’

McCain also suggested some evasiveness on Obama’s part: ‘‘Nailing down Sen. Obama’s various tax proposals is like nailing Jell-O to the wall. There has been five or six of them and if you wait long enough, there will probably be another one.’’

In one pointed confrontation on foreign policy, Obama bluntly challenged McCain’s steadiness. ‘‘This is a guy who sang ’bomb, bomb, bomb Iran,’ who called for the annihilation of North Korea — that I don’t think is an example of speaking softly.’’

That came in response to McCain’s accusation that Obama had threatened to invade Pakistan.

McCain said his rival ‘‘was wrong about Iraq and the surge. He was wrong about Russia when they committed aggression against Georgia. And in his short career he does not understand our national security challenges. We don’t have time for on-the-job training.’’

Obama countered with a trace of sarcasm that he didn’t understand some things — like how the United States could face the challenge it does in Afghanistan after spending years and hundreds of billions of dollars in Iraq.