Beyond the struggle for independents, Mr. McCain also has to work to bring in fiscal conservatives who have been drawn to Mitt Romney’s economic message. To that end, Mr. McCain will lay out in greater detail on Tuesday in Salem plans to deal with the mortgage crisis, the shrinking dollar and federal spending.

Among the proposals are repealing the alternative minimum tax, making permanent President Bush’s tax cuts, and banning Internet and cellphone taxes.

At the forum on Monday where Mr. Lieberman announced his support, Mr. McCain was in a fiery mood, ribbing Adam Kowalski, 19, for wearing a Santa Claus hat. He said, “You look kind of dorky in the hat.”

Mr. Kowalski took it in good humor and in an interview later expressed sentiments typical of many who show up at Mr. McCain’s events.

“I like his honesty,” he said. “Hearing him speak is completely different.”

An independent, Mr. Kowalski said he had not made up his mind but was leaning toward Mr. McCain, saying the senator was the only Republican he could envision supporting.

On the war, Mr. Kowalski said that he was torn, because Mr. McCain may be correct on the increase in troops, but that Senator Hillary Rodham Clinton and Mr. Obama might have the best answer in trying to end the war.

“All I know is that it is either all or nothing with Iraq,” he said.

Although some polls a few months ago showed Mr. McCain barely registering, more recent surveys suggest that he is gaining support nationally. He appears to be in a particularly strong position in New Hampshire, tied for second with Rudolph W. Giuliani behind Mr. Romney, according to a CNN/WMUR poll.