A few would get an Article 15 for a DUI. Depending on the level of their security clearance, they'd lose not just the clearance but their position and would be reassigned to an admin or protocol role until they fulfilled their Active Duty Service Committment (ADSC).
If a lieutenant, they wouldn't be promoted to captain and would be discharged at the four year mark. If already a captain, they'd be discharged at the end of their ADSC which was usually two years incurred from their Date Arrived Station.
(Pilots and navigators had longer ADSCs and depending on staffing shortages, would be kept on board since rated captains could serve twenty years without being promoted to major).
But - Publius - you're talking about the '70s and the services was loaded with the dregs at the tail end of Vietnam. We finally flushed the drug dealers, thieves, and race rioters out of the Corps in 1975 when Gen Wilson finally gave us the tools to get rid of all that detritus.
I have certainly held Office Hours (Article 15) a number of times as a battalion commander. The funniest one was when a corporal of mine repeatedly got in fistfights with his wife in public. I'd warned him before and he got in another one, so he came before me and his wife showed up too. She was big bruiser and she said "I'm not an inconsiderable woman - and I can beat any man in this room".
I said to the corporal's 6 foot 2 Captain battery commander "OK Mike, twenty bucks on you, 3 out of 5". After the laughter died down, the corporal lost a stripe.
Marriage made in heaven, I guess.