The Arizona Republican bashed President Donald Trump's White House as an "administration in disarray" while attending a security conference in Munich. Then, on NBC's "Meet the Press," he blasted Trump's attacks on the media, saying "the first thing that dictators do is shut down the press."
The sharp critiques of the President come as McCain sheds his campaign-trail reluctance to criticize Trump -- or even say the then-Republican nominee's name.
McCain, who was the party's nominee himself in 2008, has long been comfortable on the bad side of presidents. The Armed Services Committee chairman trashed George W. Bush's tenure over his handling of the Gulf War and the mounting national debt and constantly accused President Barack Obama of weak leadership abroad.
"I'm the one that said Ronald Reagan shouldn't send Marines to Afghanistan," McCain told CNN
in early February. "I'm the one that said Donald Rumsfeld should be fired. I've said the general in Afghanistan should be fired. Look, I have done what I have done right for this country under Republican and Democrat presidents. I will continue to do so. This is not a departure from the way I've conducted myself in the United States Senate."
Trump made clear he viewed McCain as an opponent in 2015, when he belittled the senator's five years as a prisoner of war in Vietnam by questioning McCain's "war hero" status, saying, "I like people who don't get captured."
McCain's response was muted. He skipped the Republican National Convention but continued to say he'd support the Republican nominee -- at least, up until the emergence of the "Access Hollywood" video in which Trump bragged about sexually assaulting women.
But since McCain won re-election, that's all changed.
In Munich on Friday, McCain fretted about "the growing inability, and even unwillingness, to separate truth from lies" -- a clear shot at Trump, who has espoused falsehoods about crowd size, voter fraud and more.
Trump sometimes "contradicts himself," McCain said, adding, "So we've learned to watch what the president does as opposed to what he says."
On Sunday's "Meet the Press," McCain joked that he hates the press, and host Chuck Todd "especially," but defended the role of journalists in society when asked about Trump's tweet Friday that the "fake news media ... is the enemy of the American people" and similar remarks he made at a rally the following evening in Florida.
"If you want to preserve democracy as we know it, you have to have a free and, many times, adversarial press," McCain said. "And without it, I am afraid that we would lose so much of our individual liberties over time. That's how dictators get started."
"They get started by suppressing free press," McCain continued. "In other words, a consolidation of power. When you look at history, the first thing that dictators do is shut down the press. And I'm not saying that President Trump is trying to be a dictator. I'm just saying we need to learn the lessons of history."
It's not the first time McCain has slammed Trump's presidency.
He hammered Trump over a reportedly contentious phone call with Australian Prime Minister Malcolm Turnbull, called Trump's travel ban a "self-inflicted wound in the fight against terror," and said the President's first major military decision -- a raid in Yemen that, in addition to killing more than a dozen al Qaeda fighters, left a US Navy SEAL, and 8-year-old girl and nearly two dozen civilians dead -- couldn't be qualified as a success.
Still, McCain hasn't personally thwarted any elements of Trump's agenda, yet.
While McCain, South Carolina Sen. Lindsey Graham and Florida Sen. Marco Rubio cast the fate of Trump's nominee for secretary of state, Rex Tillerson, into doubt, McCain has only voted against one Trump nominee, budget director Mick Mulvaney. And Mulvaney was confirmed anyway.
And at times, McCain has heaped praise on Trump, showing the limits of his intra-party criticism and underscoring why Democrats can't count on the senator to consistently undermine the President.
In a statement Monday afternoon, McCain called Trump's choice of Lt. Gen. H.R. McMaster to replace Michael Flynn as national security adviser an "outstanding choice" and heaped praise on Trump's entire national security team.
"I give President Trump great credit for this decision, as well as his national security Cabinet choices. I could not imagine a better, more capable national security team than the one we have right now," McCain said.