The Geneva convention can be side-stepped even in armed combat, for example Afghanistan and the Taliban, simply because it is an agreement between states, and if you do not recognise your opponent in this way, for example ISIS, then the protections of the GC do not apply to combatants.
The UN Convention on Torture which the US signed in the 80s is not quite as simple to dodge, hence the use of foreign installations so the US can pay lip service to meeting its requirements while torturing the crap out of whoever they fancy. But with a president who is a vocal advocate of waterboarding, I’m not sure how long that particular charade can go on.
The US can, and will do what it wants, claiming to be a humane democracy while doing the precise opposite in some hellhole prison in north Africa.