Thomas Shannon was the number three official in the State Department — until he quit in June, joining a growing wave of top diplomats who have departed their posts.

That meant he was at home when President Donald Trump met with Russian President Vladimir Putin on Monday and told the world that he trusted Putin’s word over that of the American intelligence community.

“That was distressing,” Shannon told VICE News in his first interview since leaving office. “Because I was part of a larger evaluation of Russian interference, or efforts to interfere, in our election. And I have no doubt about it.”

He added, “In many ways this was kind of a wink heard round the world. Winking at Russian behavior which should not be winked at — it should be called to account.”

Shannon spent more than 34 years in the foreign service, much of it in posts across South and Central America. His retirement, he said, was purely a personal choice.

Meanwhile, his experience at the top level of the Trump administration has left him wary, though not quite ready to declare Trump a threat to the nation, like some of his former colleagues.

“Personal diplomacy is not new,” he said of Trump's approach to world affairs that the President has embraced. “It's what Franklin Roosevelt attempted to do with Stalin towards the end of World War II. And, in regard to Putin, it's what George W. Bush attempted to do…. But personal diplomacy can only take you so far. It can start a conversation. Can break through some initial resistance. But after that you really have to have your diplomats and your other members of your national security team sit and begin to work out the issues and the problems and look for ways to to address them. And that really is going to be the challenge here."

This segment originally aired July 17, 2018 on VICE News Tonight on HBO.