All of that stuff is handled a lot farther down the food chain, I believe. Obama probably didn’t even know who he was talking to until they handed him the phone and he looked up at the teleprompter.
That being said, I’m surprised the military took someone with a DUI. I’m pretty sure if you get one while you’re in, you’re out.
Whether or not a DUI matters depends on how bad they want you, and how bad they want to keep you. You can get an enlistment waiver for pretty much anything short of an unpardoned felony, if your qualifications make it worth the trouble. For people already in, it’s the commander’s decision whether they go rehab track or discharge track. A PFC rifleman is automatically toast. A field grade destined for bigger and better things can probably get a pass, unless they need to make an example of someone.