Presidential candidates John McCain and Barack Obama yesterday continued the edgy conversation they had started in their debate Tuesday night, with the Arizona Republican senator questioning Mr. Obama's honesty and the Illinois Democratic senator shrugging off his opponent's attacks.

Speaking at a rally before a fervent, turn-away crowd of 6,000 at Lehigh University in Bethlehem, Mr. McCain portrayed the Mr. Obama as an evasive character who has taken multiple positions on numerous issues.

"He has even questioned my truthfulness," Mr. McCain, who was joined by his running mate, Alaska Gov. Sarah Palin, told his Lehigh Valley supporters. "And let me reply in the plainest terms I know: I don't need lessons about telling the truth to American people. And were I ever to need any improvement in that regard, I probably wouldn't seek advice from a Chicago politician."

Mr. Obama, speaking in Indianapolis, struck a familiar chord of his own, telling supporters that the Republican ticket offered voters more of the same.

"I can take four more weeks of John McCain's attacks, but America can't take four more years of John McCain's George Bush policies," the Democrat said. " ... We've seen where that's led us, and we're not going back."

In Bethlehem, Mr. McCain delivered a blistering indictment of Mr. Obama, reprising many of the attack lines he first used Monday. Even so, he indicated that there were limits to what he considered fair game.

Before the Arizona senator arrived at the rally, one warm-up speaker, Lehigh County Republican Chairman William Platt, twice referred to the Democratic nominee by his full name, "Barack Hussein Obama." The use of Mr. Obama's full name is widely seen as an attempt to spread the false rumor that he is a Muslim.

Mr. McCain, who has disavowed the tactic in the past, did so again yesterday -- quickly issuing a statement under the name of Paul Lindsay, his Pennsylvania spokesman. The statement read: "We do not condone this inappropriate rhetoric, which distracts from the real questions of judgment, character and experience that voters will base their decisions on this November."

Perhaps the toughest words of the day came from Delaware Sen. Joseph R. Biden Jr. At a rally in Tampa, Fla., the Democratic vice-presidential nominee described Mr. McCain as "an angry man, lurching from one position to another."

In addition, Mr. Biden mocked Mr. McCain's repeated assertion that he is and has been independent of President Bush, borrowing a phrase first used by Pennsylvania Sen. Bob Casey at the Democratic National Convention. "You can't call yourself a maverick when all you've ever been is a sidekick," Mr. Biden said.

The two presidential campaigns also engaged one another over the merits of the Homeowner Resurgence Plan that Mr. McCain proposed during the debate. As the Republican nominee described it, his idea would call upon the federal government to buy up bad mortgages and work with homeowners to renegotiate them in a way that reflects the home's reduced value.

"The dream of owning a home should not be crushed under the weight of a bad mortgage," Mr. McCain said yesterday. "The moment requires that government act -- and, as president, I intend to act quickly and decisively."

Douglas Holtz-Eakin, his senior economic adviser, said the plan would utilize $300 billion of existing refinancing authority from the Federal Housing Administration and seek to give beleaguered homeowners affordable, fixed-rate mortgages.

But the Obama campaign, after initially embracing the idea as similar to one the Democratic candidate had talked about two weeks ago, yesterday said the proposal would waste billions without really helping the situation. Jason Furman, Mr. Obama's chief economic policy adviser, said, "John McCain wants the government to massively overpay for mortgages in a plan that would guarantee taxpayers lose money, and put them at risk of losing even more if home values don't recover." He called it "erratic policy-making at its worst."

Polls taken after Tuesday's debate indicated that voters tended to see Mr. Obama as winning the faceoff. In the national horse-race polls, Mr. Obama leads by an average of 5 percentage points. The final debate will be Wednesday night at Hofstra University in Hempstead, N.Y.