How the Army officer who testified against Trump could end up in a court-martial

1SG Jerry Healy - From the article:

He is likely protected from legal ramifications from showing up to testify, a former Army judge advocate told Military Times on Thursday. But it remains to be seen whether what he told legislators could get him charged with a crime ― and, of course, how his choice to rebel against his White House chain-of-command will affect his career.
“It’s not far-fetched,” Sean Timmons, a managing partner at Tully Rinckey, said. “It’s a murky issue.”

The Military Whistleblower Protection Act prohibits government officials from interfering with a member of the military in communicating with Congress or an inspector general. Adding to the complexity is that the president gets to determine what is and isn’t classified.

The tricky thing is, according to this, is whether or not it was "manifestly unlawful" the order to not testify or Trump used his executive authority to prohibit communication of information that the executive determines "classified, sensitive, top secret..."

It's a bit of a grey area but I don't think he'll be charged by the military. As someone stated, he probably just won't progress further in his career.

SFC Kelly Fuerhoff - Hard to say about career impact, as we all know that is a nebulous thing. But if for some reason his 20 year career comes to a close, it is a pretty safe bet that this officer made a friend or two in the course of things that will assure his continued success, in or out of the Army.
Ain't no way this guy comes up on UCMJ unless he screwed up and did something illegal. Even then, he has got a lot of top cover.

SGT John Sprague - This is pretty hypothetical, but if he had a meeting and was coached, as you say, that would by a misdeed by the Congressmember, not the officer. What's the officer going to say, no thanks to a sitting member of Congress?

SGT John Sprague - That would be perjury and would warrant criminal action.

Yeah I know but don’t be surprised this kind of talk is floating around the same circles that call him a traitor and spy.

MAJ James Woods - Well, since hyperbolic language is "en vogue" these days...

LT Brad McInnis That’s what one expects to see and hear on commentary shows on Fox News and MSNBC these days...alternative facts.

It's unfortunate, but his career is over. That's the price you pay for doing whats right sometimes.

SPC Angela Burnham - Problem is, we are not going to legally know what right looks like for sometime if ever. The Democrats control the House where the Impeachment will likely succeed and the Republicans the Senate where the trial is he will be found not guilty. Who do you believe? At the end of the day, the people that supported the President through the Mueller Investigation, through this impeachment will still support him unless the Senate finds him guilty. The same people that thought he was guilty with Mueller and now, well they will still not like him. Millions of dollars later, I suspect we still will not have solved immigration problems, the healthcare fiasco, and California will still be on fire.