No one in the US refuted the Geneva convention. The issue was does it apply to terrorists who are not soldiers as defined in the convention and do not represent a nation that has signed the treaty that is the convention. While I think not broadly applying the convention as a basic demonstration of commitment to human rights is something that must be approached with extreme caution, not applying it to terrorists is not a rejection of the convention by any means. There are legitimate issues about how to deal with people who commit obviously brutal crimes and answer to no lawfully recognized international body be it country or organization.

Regards,
Mark