We all know how Republicans conduct campaigns.  Not just the Rove/Bushes or Baker/Bushes - but almost any Republican.

The mindset is distinctly Manichean.

The rationale is:

   1.  Republicans are supposed to Win
   2.  Republicans are "Good for America!" 
   3.  Therefore, anything I do to win serves America.

The path is a bright line.  If it were logical, it would be inescapable.

There is nothing they won't do or say.  I am cynical, but this is fact.

Mark Schmitt, at The American Prospect, puts it this way  -  there is no cost to them for going to extremes, and no advantage to them for decorum.

This is going to be the nastiest, lowest, meanest campaign ever.