I have the utmost respect for the Armed Forces. I've worked on many a government contract that involved the military, and while I've never had a bad experience, I've had plenty of experiences with white supremacists in the armed forces – both personally and professionally.
Unfortunately for Mr. Pentland, the entire Army is in the middle of a "stand-down" – a suspension of normal business to ensure that every single soldier, leader, and civilian employee gets into a mandatory, in-person training session to make sure that everybody knows the Army leadership's position on this super-important topic: extremists and white supremacists.
Not only is Mr. Pentland in a leadership position where he knows better, but, he's a drill instructor, a position that is meant to represent the best qualities of the Army. He might have had a chance of getting away with something like this if it had stayed quiet, but, now he's internet famous: his face, name, and occupation as a soldier are everywhere. Not only that, he was arrested for assaulting a civilian on camera. His commanding general knows his name, now. There are only two occasions when a commanding general knows the name of any random given soldier out of the thousands of soldiers under his command - either that soldier has done something exemplary, and is being recommended for some kind of award or honor...or that soldier has done something extraordinarily bad. Trust me when I say you do not want to be the soldier who has done something so extraordinarily bad that the commanding general of your post knows your name.
To make matters worse, his actions and words in the video do a pretty convincing job of painting him, at best, as exactly the kind of person the current stand-down is telling us to watch out for and, at worst, an outright white supremacist; what makes this even more popcorn-worthy, his commanding general is a black man.
The Army is going to let the civilian justice system have their pound of flesh. He's been arrested and charged with 3rd-degree assault. As I understand it, he's already been released on bail, but a conviction will carry a fine and/or a jail sentence of "not more than five hundred dollars, or imprisoned for not more than thirty days, or both," according to South Carolina law.
Once the criminal justice system is done with him, the victim has the option of suing him in civil court, as well.
After that, the military justice system can get involved. But, Ian, you ask, what about Double Jeopardy? My friends, double jeopardy doesn't apply to the military. You absolutely can be arrested, charged, tried, convicted, and sentenced for exactly the same crime twice; once by civilian authorities, and once by military authorities. He could be court-martialed. He could face time in a military jail, if the Army has a mind to make an example out of him.
If I had to guess, I'd say more than likely he'll be facing what's known as an Article 15 - that is, officially reprimanded and punished by a field-grade officer (Major or above), who in this case would likely end up being his battalion or brigade commander, at the direction of the commanding general. An Article 15 could ruin his life. Not only could he face a dishonorable discharge, he could lose his retirement pension, and he could be busted in rank down to Private. He could forfeit all pay and allowances.
Just a dishonorable discharge alone could ruin his life. That will ensure no retirement pension, and also no VA benefits once he's separated from the Army. No medical care, no VA home loans, and no education benefits, to name a few. On top of that, anyone who checks up on his military career can see the dishonorable discharge, and it will likely make him ineligible for a lot of employment as well as the ability to own a firearm. He obviously won't be able to get a job working for the DoD, and even in the civilian world, he'll likely have a real hard time getting anything that requires any kind of security clearance or background check.
The Army - now more than ever - wants desperately not to be associated with extremist and racist behavior. This guy could not have picked a worse time to make himself a very public target. Even if (and I don't believe this for a second) race had nothing to do with this, you've still got an Army drill sergeant on camera assaulting a civilian who is a third his size, who is being nothing but calm, passive, and respectful throughout the ordeal, and threatening him in no uncertain terms with physical violence. Add to the assault itself that this very public display resulted in the arrest of this Army drill sergeant, and a very public outcry from the community. I'd venture to guess that the commanding general makes an effort to build a good relationship with the surrounding community where his soldiers and their families live and work and go to school. He just dropped a PR disaster right in the commanding general's lap.
This guy's not just fucked with a capital F, he's just pissed away 25 years of his life away.
I grew up in an area where white supremacy was just a part of growing up, and I'm fairly certain that members of my family are still racists on the inside, even if they're outwardly non-racist to this day. De-programming yourself from that mindset is more than a week long class that's socially distanced powerpoint presentations: it takes time, effort, and a desire to be a better person internally.
You can be the difference you want to be in this world, even if nobody else joins you. His actions are inexcusable.