I've now heard Dodd and Clinton say that the president takes an oath to defend the Constitution and the territory and people of the United States. This is the president's oath of office:
I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States.
I would think that one basic requirement of assuming the presidency is to know the oath, wouldn't you? If forced to pick between defending the territory of the US and the Constitution of the US, your oath is to pick the Constitution.