If an American were to arrive at a US border post from Canada,?
My guess is that they'd hold you until psych eval was available. If you aren't going to say anything other than that, you won't get far. They'd check prints, try to establish your identity. They'd ask you a ton of questions, but that'd be useless since all you can say is, "I'm American, leme go home." They could do facial recognition I suppose, if that is available to them. They could match that to the passport photo. I suppose they could DNA swab and try that path, compare it to DNA database of criminals. I think I might compare passport entries into Canada, subtract all the passports that have returned to narrow down the list of possibilities, compare images. That's assuming you have a good idea of the entry date, could take a while with no timeline.Ulitmately you would not gain access without positive identification, you would be held in limbo, becuase you can't prove you're a Canadian or a US Citizen. Probably at an INS holding center, where you'd be questioned more, with no responses. I think detention, then maybe they show your face on the national news, see if anybody knows you. Someone will eventually come forward to say you are a citizen and can prove it. You'll be released and probably be required to seek help for being unable to say anything other than, "I'm American, let me go home." --fin