I am a contractor, I did not take this oath.
I didn't think so.
I've never been a contractor; always worked for the glorious federal government (NSA, did you catch that clear sign of respect?).
It seems to me that an easy way to get around anyone who might have scruples about their oath to defend the Constitution against enemies foreign or domestic, would be to have contractors do the dirty work.
The clause in their contract to not disclose classified information is just that: a contract, with penalties for not fulfilling it.
At least they won't burn in hell for telling all, just some time in jail and a check to fedgov.
I'm a contractor, and I did... it went something like...
"I, Tijeras_Slim, pledge allegiance to Hedley Lamarr, and to the evil for which he stands."
me to, neither did I