MIAMI  The strange tale of Joe the Plumber unfolded a bit more on the campaign trail Friday when Senator John McCain used a rally here to defend the Ohio man he made a national star of by focusing on him in Wednesday night’s presidential debate.

The man, Joe Wurzelbacher, gained fame after he met Senator Barack Obama recently and expressed concerns that Mr. Obama’s tax plans would hurt him if he ever became wealthy enough to buy his own plumbing business. Mr. McCain seized on the encounter at the debate to highlight the fact that Mr. Obama’s tax plan  which would cut taxes on 95 percent of Americans  would raise the taxes on small businesses. The Obama campaign countered that Mr. Wurzelbacher in fact stood to get a bigger cut under their plan.

But under the glare of the ensuing media spotlight, reporters found that Mr. Wurzelbacher did not actually have a plumbing license, and that he actually owed some back taxes. Mr. McCain leapt to his defense here Friday in a rally at Florida International University  and made another leap by suggesting that the Obama campaign was somehow maligning the plumber whose vote Mr. Obama has sought at a campaign stop in Ohio.

“The response from Senator Obama and his campaign yesterday was to attack Joe,” Mr. McCain said. “People are digging through his personal life, and he has TV crews camped out in front of his house. He didn’t ask for Senator Obama to come to his house. He wasn’t recruited or prompted by our campaign. He just asked a question. And Americans ought to be able to ask Senator Obama tough questions without being smeared and targeted with political attacks.”