Georgia U.S. Sen. Johnny Isakson took a not-so-subtle jab at President Donald Trump and examined his own actions in the Vietnam era in an impassioned and remarkably candid tribute to his late colleague John McCain on the Senate floor Monday afternoon.

The third-term Republican framed McCain, who lost his battle to brain cancer over the weekend, as a selfless patriot and fiercely vowed to protect his legacy.

“Anybody who in any way tarnishes the reputation of John McCain deserves a whipping,” he said.

And in what appeared to be a shot at the president, who feuded with the Arizona Republican and received five Vietnam draft deferments, Isakson said “most” of McCain’s detractors “didn’t have the guts to do the right thing when it was their turn.”

“So I would say to the president or anybody in the world, it's time to pause and say ‘this was a great man,’” Isakson said. “He gave everything for us. We owe him nothing less than the respect that he earned.”

The comments were remarkably pointed for the typically genteel Isakson, who has endorsed Trump but largely kept the president at arm's length.

Trump upended years of custom when he flew White House flags at full-staff on Monday and declined to issue a statement honoring McCain’s legacy. He later reversed himself after sustained media coverage and outrage from veterans groups such as the American Legion.

Isakson's remarks came as he and Georgia colleague David Perdue urged colleagues to slow debate over a proposal to rename the Russell Senate Office Building in honor of McCain. Isakson said "we owe it to the McCain family to talk about John McCain and his contributions to the country and not anything else, and that's what I intend to do."

‘Tragic to me’

In his floor speech, the Senate Veterans Affairs Committee chairman was also notably critical of his own choice to join the Georgia Air National Guard in 1966, a time in his life that he usually speaks about with pride.

He said he wanted to get married and serve the country “in a way that would not put me in as much risk to go to Vietnam as it would to be drafted.”

Isakson said he “tried to do what I could” but that his service was never in the same league as McCain’s, a naval aviator who was a prisoner of war for years in Vietnam, or his friend Jack Cox who died in the war.

“What I am telling you is tragic to me, and I apologize to everybody that I didn’t do everything that I should have done,” Isakson said.

Isakson also discussed McCain’s famously crude vocabulary and recounted traveling with him to a security conference in Munich, where he watched McCain “talk to Vladimir Putin like they were next-door neighbors” or “Dutch uncles.”

“I was so proud to be in a country that had a guy like John McCain who could break the ice with the toughest of our adversaries, speak up with pride for America and calm down when they needed to be called in,” Isakson said.

Here’s a link to the complete speech: