The only President I've ever heard criticize another was Carter. Granted, I may have missed it before but Carter stood out in my memory. Now Clinton starts an attack and Trump responds. Obama has already come out and said he intends to remain in the spot light and call out Trump if he needs thinks his legacy is at stake.  Trump ran on rolling back most of his legacy so we can expect an outspoken Obama post presidency.

With the exception of Trump, why is it that it is the democrats that have no respect or civility towards other presidents?  I know, it's because democrats are right and conservatives are wrong.