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.

Playing off the second of three debates, the Obama campaign released a TV ad 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.