Clapper was speaking to reporters Wednesday at a National Press Club event in Canberra, Australia, carried by Sky News, and offered a stark assessment of the scandal gripping Washington as he recalled living through Watergate.
"I was on active duty then, in the Air Force, as a young officer, and it was a scary time. But it was against the backdrop of all the post-Vietnam trauma as well, which seemed at least in my memory amplified -- as a backdrop -- amplified the crisis in our system," Clapper said.
"I have to say, though, that I think when you compare the two, that Watergate pales really in my view compared to what we're confronting now," he added.
Clapper also shared concerns with what he called "the internal assault on our institutions," citing Trump's January tweet comparing the intelligence community to "Nazis" and "the whole episode" with the firing of FBI Director James Comey.
After Trump "disparaged" the intelligence community with that "absurd allegation" in the January tweet, Clapper said he "felt an obligation to defend the men and women of the United States intelligence community. So, I called him on 11 January. Surprisingly, (Trump) took my call."
Clapper continued, "I tried, naively it turned out, to appeal to his 'higher instincts' -- by pointing out that the intelligence community he was about to inherit is a national treasure and that the people in it were committed to supporting him and making him successful. Ever transactional, he simply asked me to publicly refute the infamous 'dossier,'
which I could not and would not do."
Clapper also sharply condemned a speech Trump gave
before the memorial wall in CIA headquarters that commemorates employees killed in the line of duty.
"He chose to use that as a prop for railing about the size of the inauguration crowd on the Mall, and his battle with the 'fake news' media. His subsequent actions -- sharing sensitive intelligence with the Russians, and compromising its source, reflect ignorance or disrespect -- are likewise very problematic," Clapper remarked.
Regarding Comey's firing, Clapper called the former FBI director a "distinguished public servant" and slammed Trump's decision.
"Apart from the egregious, inexcusable manner in which it was conducted, this episode reflected complete disregard for the independence and autonomy of the FBI, our premier law enforcement organization," Clapper said.
"So, as I said, I worry about these assaults on our institutions," he added.