[secretagent]

Assuming you had the opportunity and requisite nerve, would you have assisted fugitive slaves in their flight to Canada, knowing that you thus violated the Constitution?

If yes, doesn't that point to principles superior to the "principles of the Constitution?

[P_A_I]

The practice of slavery was an exception to the principles of liberty in the Constitution.
Assisting escaping slaves did not violate those principles, it violated the exceptional 'property rights' of slave owners.

>>> Are there principles superior to the "principles of the Constitution"?

There should be no conflict between the "principles of the Constitution" and any that you might personally believe "superior".
If you see such a conflict, perhaps you should re-examine your concepts about both.
I've heard that military Chaplin's are very good at explaining how duty to our country & Constitution can be reconciled with an individuals personal beliefs.