So, the 'lacking experience' attack not having worked, McCain wants to make the case that Obama has bad judgment.  He lights upon Ayers as a case in point. He makes the case, and makes it again and again.  By not being able to cite other examples of bad judgment and show a pattern -- and the this goes also for the subliminal connection to 'terrorist' -- what McCain has done is use up the effective power of the example.  He did the same thing with "I'm a POW."  Even worse for McCain, people begin to wonder that if Ayers is the only case of bad judgment, then there probably isn't so much to the Ayers case, and Obama must have pretty good judgment after all.