Despite much of the training that is going on right now in the military known as SHARP training (Sexual Harassment and Assault Response Prevention) training, despite those educators putting forward that all sex with a person who has consumed alcohol is a crime, that is not in fact the case. Under the UCMJ, it is not a crime to have sex with a person who is in fact drunk.
What is a crime under the UCMJ is if that person has become so intoxicated that they have reached a level where they are no longer legally capable of consenting. The easiest example occurs when the person reaches a level of unconsciousness, that is they are passed out. But it is not illegal under the UCMJ as of right now to have sex with a person who is intoxicated.
What becomes problematic with making the decision to engage in sex with a person who has consumed alcohol is that you are putting yourself at risk for the potential later that the person regrets their decision that they made under the influence of alcohol to have sex with you.
If an allegation is made and if military law enforcement begin to look into the decisions that you made over the course of that evening and into that morning, you may find yourself under investigation for an allegation of sexual assault. At that point, you may have a room full of strangers trying to decide if in fact that person legally was in a position to consent.