David Gergen has been a White House adviser to four presidents and is a senior political analyst at CNN. In that moment, the difference between Trump and former Presidents Richard Nixon and Bill Clinton became starkly clear. David GergenIt's clear that Nixon and Clinton behaved very differently from Trump when faced with impeachment proceedings that clouded their presidencies. During their respective impeachment inquiries, both Nixon and Clinton ultimately cooperated with authorities. He has not turned over a single document to Congress and the White House has blocked key witnesses from testifying.

Source: CNN December 22, 2019 00:56 UTC