One of the things that military personnel — and especially officers — have drummed into them from day one is to "respect and follow the chain of command." For officers (and senior enlisted), though, there's a subtle exception; that subtle exception calls on the highest standards of professionalism. "If there's a problem and the chain of command is compromised or unable to act, use the Inspector General system."
And so Lt Col Vindman did. He exercised his professional judgment after personal observation of unlawful command influence, determined that directly following the chain of command would be futile concerning those unlawful orders, and properly utilized the IG system that was available to him.
That obviously has not been cost-free to Lt Col Vindman. He'll be better than "just fine" in the long run, but the probability of ever getting promoted above O–5 under the strictures imposed by DOPMA has dropped below 20% no matter how outstanding his performance and no matter how great his potential. (Ordinarily, by statute, it is purportedly "50%," but that's a mischaracterization of the mechanics of DOPMA; it's actually just about 45% for line officers who make O–5 on time or "below the zone" (early promotion) in the first place.) And promotion to O–6 requires specific approval, by name, by the Senate. Yes, it's a list that is presented as part of a resolution… and every year, for every service, a few names get quietly removed from that list, usually for good cause but not-infrequently for less than good cause. Like political embarassment.
So congratulations, Senator Blackburn (R–TN): Your vendetta has and/or will deny the apparently appropriate services to the United States of a man who appears to be what we actually want in senior officers, at least after he reaches his 28th year of service. In this instance, he did precisely what military protocol demanded of him; but, with your nonmilitary background and constricted experience and educational baseline, you didn't understand that. And weren't interested in understanding that; you didn't understand any of the lessons of Iran-Contra, nor did you understand that a military officer just does not object to disagreed-with command actions via press conference or antisocial media frenzy. Like you do/did.
<SARCASM> I'm not going to stoop to your level, Ms Blackburn, and "suggest" that you are from a "hunting-happy" state that has no licenses for and no limits on self-aggrandizing politicians and that its citizens should consider that, because that's not a solution here. Machine politics would just throw in an equally ignorant replacement, and advocating violence isn't appropriate in the first place. Which didn't stop you. </SARCASM> You have brought shame and disrepute upon the United States Senate… although in this environment, you've had a lot of competition in doing so.