NEW YORK – John McCain hung his final presidential debate performance on an Ohio plumber who campaign aides never vetted. A day after making Joseph Wurzelbacher famous, referencing him in the debate almost two dozen times as someone who would pay higher taxes under Barack Obama, McCain learned the fine print Thursday on the plumber’s not-so-tidy personal story: He owes back taxes. He is not a licensed plumber. And it turns out that Wurzelbacher makes less than $250,000 a year, which means he would receive a tax cut if Obama were elected president. McCain likes to say that he isn’t...