you shut up
When the president ignored Vindman's opinion, Vindman violated national security to complain about Trump's chosen policy approach. (And note, please, that he did not protect himself by being an official whistleblower. Instead, he whined to someone else.) Then, when called before Congress, the man who wears a suit to work showed up in his uniform, evidently trying to put the military's imprimatur on his personal mutiny.
Guess he learned the truth behind Ralph Waldo Emerson's reminder that "when you strike at a king, you must kill him." Alexander Vindman, in addition, should be thanking his lucky stars that he hasn't been court-martialed (or at least hasn't yet been court-martialed).