Bill Maher points out something worth noticing: What constitutes a political "gaffe" -- that is, something a politician does or says that's treated as a serious mistake that makes them look bad -- has changed quite drastically when it comes to Donald Trump.
One of Maher's examples comes from a joint television interview in which Bob Dole asked George H.W. Bush to "stop lying about my record." That reminded me that I once heard in interview in which the elder Bush sincerely lamented having lost a friend he had campaigned against because the man was upset by things Bush had said about him. Bush said those remarks had been "just politics," and he was sorry his former friend had thought that Bush really meant what he said.
Politics had so corrupted Bush that he thought it was OK, just the way the game was played, to lie about someone in an effort to persuade voters. That's sad, and it's sad that this sort of thing works.