And he said the US experience with Russia should warn Australia about the increasing influence of China in our region and our country.
Clapper, a retired Lieutenant General of the United States Air Force, served as intelligence chief from 2010 to 2017.
And he has been extraordinarily frank about his fears for his country under Donald Trump. He referred to "well-founded concern about our current administration and its emerging foreign policy generally".
"I am very concerned about the assault on our institutions coming from both an external source - read Russia - and an internal source, the President himself."
He said he had been surprised President Trump was "inexplicably so solicitous" of Russia and its leadership after being given evidence of interference in the November US elections.
"Then President-elect Trump disparaged the intelligence community's highly-confidential assessment of the magnitude and diversity of this Russian interference that I just described by characterising us as Nazis," he said.
"This was prompted, I found, I realised later, by his and his team's extreme paranoia about and resentment of any doubt cast on the legitimacy of his
election which, of course, our assessment did."
Goaded by the "Nazi" insult, Clapper telephoned Trump to defend his agents, but instead was asked about the notorious dossier which claimed Trump had been videoed in compromising activities in Moscow.
"I tried, naively as it turned out, to appeal to his higher instincts by pointing out to the US intelligence community that he was about to inherit a national treasure in our country and that the people in it were committed to supporting him and making him successful," Clapper recalled.
"Ever-transactional, he simply asked me to publicly refute the infamous dossier which I couldn't and wouldn't do."
He said Trump had told him it would be "a good thing if we could get along with the Russians".
But he couldn't agree.
Clapper said of Russian covert strategies: "They've tried to interfere in our elections going back to the '60s but, let me stress, never like they did in 2016.
"Apart from the infamous hacking of the Democratic National Committee, their campaign had many other dimensions - social media trolls planting false information, orchestrated fake news which many other news outlets picked up and amplified either wittingly or unwittingly, and a very sophisticated campaign by the regime-funded propaganda arm, the RT, broadcasting arm, against Hillary Clinton and for Donald Trump."
And he went further.
"The Russians are not our friends," he said.
"They and (President Vladimir) Putin specifically, despite his disingenuous denials, are opposed to our democracy and values and see us, particularly the United States, as the cause of all their problems and frustrations."
