Senator John McCain thinks Russian President Vladimir Putin, whose government interfered in the 2016 presidential election, is more of a threat to America than Islamic State terrorists.
"I think ISIS can do terrible things," the Arizona Republican told 7.30 last night.
"But it's the Russians who tried to destroy the fundamental of democracy and that is to change the outcome of an American election."
Although he has seen no "evidence" Moscow's tampering during the election was successful, he said they "tried and they are still trying to change elections."
"They just tried to affect the outcome of the French election. So I view Vladimir Putin ... I view the Russians as the far greatest challenge that we have," he told host Leigh Sales.
McCain took a further swipe at Russia for "dismembering Ukraine, a sovereign nation" who is putting pressure on the Baltic States, the New York Post reported.
He also faulted the Trump administration, which is being investigated for possible ties to Kremlin officials during the presidential campaign, for not responding more forcefully to Russia's interference by pursuing sanctions.
"We have done nothing since the election last November to respond to Vladimir Putin's attempt to change the outcome of our elections. So, way to go Vladimir. We haven't responded at all," McCain said.
Weighing in on the Russia probes and the revelation that Jared Kushner, the president's son-in-law and a top White House adviser, tried to set up a secret line of communications with Russian Ambassador Sergey Kislyak before Trump took office, Mr McCain said, "You can't make it up."
"I know some administration officials are saying this is standard procedure. I don't think it's standard procedure prior to the inauguration of the president of the United States by someone who is not in an appointed position," he said.
"This is becoming more and more bizarre. In fact, you can't make it up."
McCain, the Republican presidential nominee in 2008, also admitted Trump's unpredictable behaviour makes him "nervous from time to time."
"I do believe that the President has great confidence in this national security team. I do believe most of the time that he accepts their advice and counsel," McCain said.
"Can I tell you that he does all the time? No. Does it bother me? Yes, it bothers me."
Sales also asked if it was logical that German Chancellor Angela Merkel said Europe now needed to go it alone given Trump's behaviour and past comments.
"I have taken the practice of not reacting to what the President says but what the President does," McCain said.
The Senator said he wished Trump had also mentioned that the US was grateful for NATO's support on Article 5 which argues an attack on one is an attack on all, when he argued for an increase in European contributions.
He said when the US was attacked on September 11, their allies invoked article 5 and "came to our defence."
However he noted that a lot had changed since Barack Obama was in power and "our European friends" think things were fine over the past eight years and have a very different view of history.
"When America abandons its leadership then bad things happen and that vacuum is filled which evil influences. So I appreciate the European's viewpoint and their repudiation of Donald Trump but my friends, why don't they say, 'Maybe we shouldn't have given Barack Obama the Nobel Peace Prize before he was ever even elected.'"
When Sales pointed out some people were reluctant to embrace the US leadership under Trump, McCain said he was warmly received during his visit to the Middle East because they saw him a strong leader who got things done.
Sales also mentioned yesterday's latest missile launch by North Korea and asked McCain what was next.
"I don't think it's acceptable for the United States of America to have an intercontinental ballistic missile or a missile aimed at Australia with a nuclear weapon on it and depend on our ability to counter it with an antimissile capability," he said.
McCain said it was up to China to help control its wayward ally and warned things could be as bad as when they were during the Cuban missile crisis unless North Korea was stopped.