Personally, I think that *all* Americans should be required to swear or affirm to uphold the Constitution at age 18 or upon naturalization. Refuse to do so? You're given a one-way ticket to the country of your choice and a boot to the arse -- it would be considered a renunciation of citizenship. Conspiracy to violate the Bill of Rights, same deal. Passport burned in front of your face, and a one-way ticket to a country that you deserve more.

Anyway, sometimes breaking the law (or an NDA) is the right thing to do. Example: if you signed an NDA working for an chemical company, and they're engaged in illegal dumping, would it be the right thing to rat to the media?