You might want to do some reading on the earliest thinkers of the Law. I think Thomas Aquinas is one,
"St. Thomas Aquinas: An unjust law is a human law that is not rooted in eternal law and natural law. Any law that uplifts the human personality is just. Any law that degrades human personality is unjust. All segregation statutes are unjust because segregation distorts the soul and damages the personality. It gives the segregator a false sense of superiority and the segregated a false sense of inferiority."
Probably might want to read up on some of the earliest thinkers of the law. Martin Luther King is an interesting one as well. He talks alot about unjust laws.
http://en.wikiquote.org/wiki/Martin_Luther_King
" * One has not only a legal, but a moral responsibility to obey just laws. Conversely, one has a moral responsibility to disobey unjust laws.
* In your statement you assert that our actions, even though peaceful, must be condemned because they precipitate violence. But is this a logical assertion? Isn't this like condemning a robbed man because his possession of money precipitated the evil act of robbery?"
Hmm.. Wish I can help more, but I never studied nor majored in Philosophy.