This post has been updated with the news regarding DOJ official Bruce Ohr.

President Trump has revoked the security clearance of former CIA director John Brennan. And he’s eager to do the same for others -- despite pushback from a bipartisan group of former top intelligence officials. The White House has already listed nine officials who could be next, and Trump said Friday that he expects to strip Justice Department official Bruce Ohr of his security clearance “very quickly.”

We know it’s controversial. But could it also put Trump in even more legal jeopardy?

Presidents generally have broad authority to grant and revoke security clearances at their will (kind of like pardon powers). And revoking Brennan’s clearance wouldn’t seem to be an obvious problem for Trump in Robert S. Mueller III’s obstruction of justice investigation -- given Brennan currently has no role in the investigation.

But that doesn’t mean Trump’s gambit isn’t legally problematic, say some experts.

I was on an MSNBC panel Thursday night with Elie Honig, a former federal prosecutor for the Southern District of New York, who suggested Trump’s revocation of security clearances could be construed as retaliation against witnesses. “It’s a federal crime -- §1513 if anyone wants to look it up -- to retaliate against someone for providing truthful information to law enforcement,” he said. “So he’s getting closer and closer to really dangerous ground here.”

Here’s the text of Section 1513(e):

Whoever knowingly, with the intent to retaliate, takes any action harmful to any person, including interference with the lawful employment or livelihood of any person, for providing to a law enforcement officer any truthful information relating to the commission or possible commission of any Federal offense, shall be fined under this title or imprisoned not more than 10 years, or both.

Honig explained to me Friday that he didn’t necessarily think Trump’s revocation of Brennan’s security clearance would be a violation, given Brennan isn’t a major figure on the probe’s key events. But if he presses on and does it with others, Honig argued, it could.

“Brennan’s not an easy fit as a witness," Honig said. "But how about Jim Comey? He’s one of the most pivotal witnesses in this whole thing. If Trump starts lashing out at Comey and all he said publicly is, ‘I’m doing this because of Russia,’ I think that can be construed as retaliation.”

The fired former FBI director would be the most obvious key witness in this whole thing, and his name is on the list of nine current and former officials whose clearances are allegedly being reviewed (even as it’s not clear Comey still even has one). Another person on that list: former acting attorney general Sally Yates, who delivered some bad news about Michael Flynn to the White House in another key event in the Mueller probe. Other experts suggested Andrew McCabe, the former FBI No. 2 who took over briefly after Comey’s firing, could also be considered a witness. He’s on the list, too.

There’s an argument to be made that revoking a security clearance for any of these officials could constitute “interference with the lawful employment or livelihood of any person,” given they may serve as pundits or in other roles where they rely upon the information gleaned from their clearances.

And Ohr might actually have the most to lose of any of these when it comes to his “livelihood.” He’s the only current Justice Department official on the list, after all, and losing his clearance would ostensibly directly impact his employment situation.

President Trump on Aug. 17 defended his action toward ex-CIA director John Brennan, warning former associate deputy attorney general Bruce Ohr could be next.

But the question, as with many aspects of the Mueller investigation, is whether the intent clearly stems from the investigation. Trump could certainly argue, in the case of Brennan, that the revocation has to do with the official’s public comments -- which was the initial explanation from the White House before Trump muddied it. He could also argue, in the case of Ohr and Comey, that it had to do with actual job performance, rather than their testimony.

“For a current government employee, revocation of a security clearance could potentially interfere with that person’s ‘livelihood,’ which is part of the statute,” said Jack Sharman, a former special counsel in the Whitewater investigation during the Clinton administration. "Nevertheless, the government must show a wrongful intent, and must also link the revocation to the provision of information to prosecutors or agents.”

And even beyond that, this all seems likely to be decided via impeachment (or not) by Congress, for which this might be a relatively minor question when compared to potential collusion and obstruction of justice.

“It’s plausible if that person was a witness for the Mueller or for the Senate or House investigation,” said Jeffrey Jacobovitz, who represented White House employees during the Clinton scandals, “but does that rise to the level of ‘high crime and misdemeanor?’”