I am going to draw an analogy that comes from my experience as a paramedic. This deals with the issue of consent - if you are unable to consent, than we can legally take you away in the ambulance against your wishes.

The criteria for ambulance-raping someone against their will involves qualifying different levels of consciousness - from fully alert to unresponsive

Within the 'alert' category, you can still be unable to give consent. Paramedics and other emergency personnel are taught to give simple questions to determine whether the person is not only conscious, but aware of their surroundings.

We call this "Alert and Oriented to 4" or "AnO to 4".

An example of this:

What's your name?

Pizza

What city are you in?

Portland

What month is it?

October

Who am I?

a medic

If the patient can answer these questions, even if they are literally falling over drunk, they are legally alert enough to their surroundings that we cannot force them to go to the hospital. If they are vomiting blood while staggering around, but they answer these questions, they are legally enough of a consenting adult to refuse medical treatment. They are considered legally sound enough to make decisions on their own behalf.

So when people say "drunk people can't consent no matter what" and others retort "drunk only means passed out" they are both wrong. There is a middle area, and when someone crosses this legally defined line and becomes incoherent, even if still walking and responsive, they can no longer give consent.

This also means that if someone is able to speak and verbally communicate a desire for sex, then legally they are NOT incapacitated. They are a consenting adult regardless of what their BAC is or how otherwise impaired they are. Impaired is not incapacitated.