"Alcohol removes the ability to make decisions under the law."

This is not true, particularly in criminal law. If alcohol "removes the ability to make decisions" then one might think that people who committ crimes under the influence of alcohol have not made a 'decision' to committ a crime, and thus lack 'intent' or culpability for their drunken actions. It generally doesn't work this way -- try claiming that you were so drunk that your "decision" to drive shouldn't be held against you.This raises an issue others have pointed out -- what if a drunk man has sex with a sober woman? Has she committed 'de facto' rape? This raises a plethora of legal questions about general and specific intent, etc. etc.

Another big problem is that people often assume that terms like "drunk" are easily translatable into legal use. Generally speaking the word "drunk" never shows up in the penal code. For purposes of driving a motor vehicle there is often a "presumption of intoxication" at a certain blood alcohol level. But other than that "under the influence" is a very fuzzy concept, one that jurors often have to struggle with. Perhaps we should have a "Sexing under the influence" law, where it is illegal to have sex when one is "impaired to the slightest degree in their ability to safely have control sex." In addition, there far less likely to be any 'scientific' evidence of intoxication in a rape case (like, say, a breathalyzer score taken with two hours of the event).