I highly doubt your professor actually suggested you break the law - that would be pretty stupid as if you are training to become a professional, having criminal convictions won't exactly look good on your record. I agree with the above poster in that its important to get to know whats behind a cause - you have to be able to truly connect with those who you'll be advocating, campaigning for the sake of campaining is pointless and you would be better off dropping the class. Is there anything in particular that angers you? Is there something you think is really misguided or being carried out inappropriately? For me theres so many things i want to be involved in improving; the attitude to gay marriage/adoption, the rights of prisoners, domestic violence, the underfunding of schools and other public services, immigration laws etc. I hope you find a cause that speaks to you. All the best.