It is the duty of all citizens to defend the Constitution.
What they should do is mandate the oath of allegiance:
http://en.wikipedia.org/wiki/Oath_of_Allegiance_(United_States)
Of course, the last line is under question, if they can't get the diploma if they don't swear, then is it really given with reservation or puprose of evasion? This could be a problem for those becoming citizens too.
I wonder why no one has ever complained since the citizenship oath has those "terrible words" at the end.
I believe all oaths the final four words can be ommited on the federal level, and in the pledge.
I have no problem asking students to swear country allegiance, and as with the federal goverment the swearing to god should be optional.
Amazing, it is outrageous to mandate oath of citizenship, but perfectly fine to require forced volunteerism(slavery) as a requirement of graduation.