It is possible, I suppose, to imagine an extraordinary circumstance in which it would be necessary and appropriate under the Constitution [...] for the President to authorize the military to use lethal force within the territory of the United States.

~ Attorney General Eric Holder

That's in response to Senator Paul's multiple requests for an official position on issuing drone strikes on American soil. I find Holder's response interesting because the Constitution I read didn't have an exemption to the 5th Amendment stating it can be ignored it if there's an "extraordinary circumstance." Perhaps there's a secret interpretation of that text too?