Joe, who is not even a licensed plumber, does not really understand Obama's tax plan, but mistakenly believes that it will adversely affect him. He became famous after Obama tried to explain to Joe on videotape that even if Joe were to find himself making over $250,000 per year, he should not be too upset about having to pay 39% of his income in taxes instead of 36% because that is fair. But Joe is not buying that explanation because he has bought into the Republican mythology that taxes are always bad, and that even middle class people should be against taxes because they might be rich some day.
Joe should be thinking about whether it is really smart to finance the US government by excessive borrowing instead of taxes, which will mean that his grandchildren will have to pay these debts back with interest. He should be thinking about whether the recession which has been exacerbated by Republican policies of lax bank regulation may be more harmful to his business than any proposed Democratic tax increases. He should be educated on how the economy almost always grows faster under Democratic administrations than Republican administrations. But instead he is afraid of the tax bogeyman that the Republicans always use to scare voters, and he is seduced by the phony promises of the Republicans that we are going to be able to cut everyone's taxes and we will never have to pay for those tax cuts. Voters like Joe have allowed the Republicans to cut the taxes of the rich by enormous amounts in exchange for a pittance in tax cuts, which end up being outweighed by job and income losses, and by government service cuts that harm people like Joe the plumber the most.
Joe the plumber's story therefore does not even support the McCain program, but since Joe is deluded enough to buy what the Republicans have been selling, the McCain camp is cynically using him to falsely claim that Obama's economic plan is bad for the average Joe. Notice that they never talk about the actual facts of Joe's situation, and in fact protest when the media has attempted to investigate the facts. Instead they are relying on a character who simply thinks he will be hurt by the Democratic program, without regard to the truth. The Joe the plumber that McCain keeps talking about is therefore no more real than the Harry and Louise commercials that were used to defeat Clinton's health care plan in the 90's. But the big lie has worked before, so McCain hopes it will work again this year.