The remarks from Kelly, a retired Marine Corps general, come after Vindman was removed Friday from his role as the top Ukraine specialist on the NSC and escorted from the White House grounds. Vindman’s twin brother Yevgeny, who served as a senior lawyer on the NSC, was also forced from his post.

Their dismissals were widely viewed among Democratic lawmakers and administration critics as an act of political retaliation after Vindman informed White House attorney John Eisenberg of Trump’s conversation with Ukrainian President Volodymyr Zelensky and proceeded to cooperate with the House impeachment investigation.

Kelly, who served as Trump’s most senior aide from July 2017 until early last year, said Vindman's decision to escalate his concerns about the call were in line with the protocol of the armed forces.

“We teach them, Don’t follow an illegal order. And if you’re ever given one, you’ll raise it to whoever gives it to you that this is an illegal order, and then tell your boss,” Kelly said Wednesday of Vindman’s flagging of the call, during which Trump pressured Zelensky to open foreign probes into his domestic political rivals.

Kelly also appeared to affirm that he believed Trump did indeed condition hundreds of millions of dollars in vital military aid to Ukraine on Zelensky’s agreement to assist in the investigations of former Vice President Joe Biden and his son Hunter.

“Through the Obama administration up until that phone call, the policy of the U.S. was militarily to support Ukraine in their defensive fight against …. the Russians,” Kelly said. “And so, when the president said that continued support would be based on X, that essentially changed. And that’s what that guy [Vindman] was most interested in.”

Trump swatted at Kelly on Twitter later Thursday for weighing in on Vindman, declaring that his former chief of staff “has a military and legal obligation” to keep silent about administration affairs.

“When I terminated John Kelly, which I couldn’t do fast enough, he knew full well that he was way over his head. Being Chief of Staff just wasn’t for him,” the president wrote. “He came in with a bang, went out with a whimper, but like so many X’s, he misses the action & just can’t keep his mouth shut, which he actually has a military and legal obligation to do.”

Trump went on to write that Kelly’s “incredible wife, Karen, who I have a lot of respect for, once pulled me aside & said strongly that ‘John respects you greatly. When we are no longer here, he will only speak well of you.’ Wrong!”

White House officials in recent days have sought to deflect backlash from the Vindmans’ ousters, with counselor to the president Kellyanne Conway asserting Monday that the brothers were not fired.

Conway told Fox News that the Vindmans remain “employed today,” but did not explain why Alexander’s detail to the NSC ended on Friday when it was previously slated to finish in July.

“They are working at the Army, where they were. They were detailed to the NSC. This is typical,” she said. “I’ve had detailees on my small staff. This is very typical in a White House to have a detailee for a temporary period of time who then returns to what their full-time job is.”

National security adviser Robert O’Brien also insisted Tuesday that the Vindmans were “absolutely” not retaliated against, and instead suggested that their removals were intended to foil alleged efforts to undermine the president.

“We’re not a country where a bunch of lieutenant colonels can get together and decide what the policy is of the United States,” O’Brien said during an event at the Atlantic Council think tank. “We are not a banana republic.”

But Trump claimed Saturday that Vindman was “OUT” because he was “very insubordinate,” reported “incorrectly” the contents of the July call with Zelensky, and “was given a horrendous report by his superior.”

The president said Tuesday that the military will likely explore disciplinary action against Vindman, telling reporters in the White House that “they’re going to certainly, I would imagine, take a look at that.”

Kelly’s comments Wednesday regarding Vindman mark his most forceful repudiation yet of Trump’s conduct during the Ukraine scandal, which resulted in his impeachment by the House in December and acquittal in a Senate trial earlier this month.

The former chief of staff expressed disagreement in his Wednesday night remarks with Trump over a variety of other topics, touching on North Korean leader Kim Jong Un, Russian President Vladimir Putin, the administration’s proposed border wall, and rhetoric related to migrants and the media during a 75-minute speech and question-and-answer session.

Kelly was also critical of Trump’s intervention in November in the cases of Navy SEAL Chief Eddie Gallagher and two more service members implicated in war crimes — an episode which resulted in former Navy Secretary Richard Spencer being pushed out of the administration.

“The idea that the commander-in-chief intervened there, in my opinion, was exactly the wrong thing to do,” Kelly said of the Gallagher case. “Had I been there, I think I could have prevented it.”

Kelly has not hesitated to break with the official White House line since departing the administration in January 2019. Two weeks ago, he said, “I believe John Bolton,” the former national security adviser who recounted in excerpts of a forthcoming memoir that Trump pursued a quid pro quo with Ukraine, according to news accounts of the book.

White House press secretary Stephanie Grisham likened Kelly to Bolton in an interview Thursday, implying that both former officials were seeking to hinder the president’s reelection prospects.

“It’s interesting that he’s starting to poke his head out and speak a little bit more, just like John Bolton, as we’re getting close to an election,” Grisham told Fox News, adding that her experiences with Kelly in the White House ran counter to his statements Wednesday.

“I was disappointed, obviously. Especially, I saw some of the comments that he made, and I was in the room with him when he actually backed the president on many of the things that he’s now saying, you know, weren’t great,” Grisham said. “Talking about the media, especially. I have heard John Kelly say some things about the media, so I thought it was a little disingenuous.”