It is a sign of the futility not so much of John McCain's campaign per se, but the use of the McCain campaign of historically tried-and-true tactics that, according to this report from New Hampshire, the robo-calls for which McCain is being lambasted just aren't working.
Call it the non-injury added to the insult.
Voters have had it with the substance-free, attack-and-distract methods perpetrated by the modern Republican Party and its conservative allies. That's why leveling anti-American charges, or using guilty-by-association insinuations, or trying to tap into terrorist fear-mongering are all ringing so hollow.
Americans seem to have finally realized that the shell game without a pea that Republicans have been using for years just ain't worth playing anymore.