Florida was McCain's first stop on a two-day tour through states, including North Carolina and Virginia, where he has surrendered his lead in polls during the past month despite their history of supporting Republican presidential candidates.
Last Sunday as Obama walked through Wurzelbacher's Holland, Ohio, neighborhood, Wurzelbacher asked him whether his plan to increase taxes on those earning more than $250,000 a year would impede his ability to buy the plumbing company where he works. Obama replied that those making over $250,000 would be taxed more but that money would be returned to the middle-class through tax cuts. "I think when you spread the wealth around, it's good for everybody," Obama said.
The McCain campaign seized on that remark.
"When politicians talk about taking your money and spreading it around, you'd better hold onto your wallet," McCain told a Miami rally crowd. "Sen. Obama claims that he want to give a tax break to the middle class, but not only did he vote for higher taxes for the middle class in the Senate, his plan gives away your tax dollars to those who don't pay taxes. That's not a tax cut; that's welfare."
McCain, who bestowed the nickname "Joe the Plumber" on Wurzelbacher during the debate, claimed Friday that "the response from Sen. Obama and his campaign yesterday was to attack Joe."
In fact, Obama, his running mate Joe Biden and their campaign have barely mentioned Wurzelbacher. Obama and Biden both attacked McCain for portraying Wurzelbacher as representative of most blue-collar workers, asking how many plumbers make $250,000 a year.
Nonetheless, McCain elicited boos from a fired-up crowd when he said of Wurzelbacher, "People are digging through his personal life and he has TV crews camped out in front of his house. He didn't ask Sen. 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 Sen. Obama tough questions without being smeared and targeted with political attacks."
News organizations eager to learn more about Wurzelbacher did besiege his house Thursday and discovered and reported that he lacks a plumbing license and owes back taxes.
During an appearance Friday evening in the Space Coast community of Melbourne, McCain revealed that he had spoken to Wurzelbacher for the first time earlier in the day.
"I want to tell you his spirits are good and he's a tough guy. He's what small business people all over this country are about," McCain said to cheers. He encouraged the crowd, "Send Joe an e-mail and tell him you're with him."
A McCain aide said later that the senator discussed having Wurzelbacher campaign with him, but she couldn't recall any conclusion being reached during their conversation.
"We'll be in Toledo on Sunday," said aide Brooke Buchanan. Toledo is the city near Wurzelbacher's hometown.
While speaking with reporters on Thursday, Wurzelbacher refused to say whether he would vote for McCain or Obama. The plumber said that was between him and "the button" in the voting booth.
Despite his criticism of the Democratic ticket, McCain himself has kept Wurzelbacher in the spotlight, mentioning him repeatedly in his appearances Thursday and then renewing the topic on Friday.
"Joe's the man!" McCain said Thursday during a rally in Philadelphia's suburbs.
Later, both McCain and Obama gave traditionally lighthearted speeches to the Alfred E. Smith Memorial Fund Dinner in New York. McCain made light of questions about the plumber's income with a joke at his own expense.
"What they don't know is that Joe the Plumber recently signed a very lucrative contract with a wealthy couple to handle all the work on all seven of their houses," said the senator, who owns that many homes and investment properties with his wife, Cindy.
In Florida, McCain got a boost from his close friend Sen. Joe Lieberman, the 2000 Democratic vice presidential nominee who now is a political independent. Lieberman, the first Jewish candidate on a major-party ticket, still has a strong following among Jews living in Florida and he came along to introduce McCain in Miami.
Later, in Melbourne, McCain reached out to the aerospace industry by pledging to spend $2 billion on aerospace projects during the period between retirement of the space shuttle and the launch of its replacment.
Noting the Chinese recently made their first space walk, he said: "We've got competition. We've got to stay ahead. We will be the first nation to Mars."
Recent surveys have shown Obama opening as much as a 5-point lead in Florida. The two are essentially tied in North Carolina, but Obama has opened a nearly double-digit lead in Virginia.
The state findings were echoed in an Associated Press-Yahoo News poll released Friday.
It showed people's regard for the Republican presidential nominee has deteriorated across the board since September, with McCain losing ground in how favorably he's seen and in a long list of personal qualities voters seek in White House contenders. Meanwhile, perceptions of Obama have improved or remained steady.