The Republicans know that they have a solid lock on some 30% of the voters, those who will tolerate or even applaud any sort of attack levelled at Obama, no matter how spurious or vitriolic.

But they are slow in learning that they are seriously putting off the middle-spectrum voters who might oppose Obama’s policies but do not see him as the Antichrist Manchurian Candidate Communo-Fascist Beast Granny Killer, etc, that he is being made out to be by the extremists.