Revolution

I feel as though any type of change will always meet resistance. People grow very comfortable with the status quo, and do not want to rock the boat or shift from what they're used to and they will fight to protect it. I also feel that if something isn't working and people aren't having their needs met then something must be done about it. Constant changes are always needed to keep up with the times which is why there are debates about changing the law and it's written in the constitution that we have a right to rebel against and unjust government if it stops serving the interest of those governed.
As far as whether or not violence is necessary, I oppose the use of harming innocent people, but violence has helped get the point across to people when they refuse to listen or it at least grasped the attention of the media and thus reaches even more people (such as terrorism, 9/11, the olympic games of 1972 where people were held hostage). At the same time, people who have tried to do peaceful demonstrations have been met with violence from those in power, such as the freedom marches, or protestors where people were harmed by the police and or military. Violence can help or hurt a cause.
Revolution needs one side to fight for it, and the other to compromise or submit to change. No growth ever came without some form of pain. I don't think changes can be abrupt where you wake up one day and say "all gays can be married now" but it happens gradually as people become more educated and concerned or as values shift one way or the other. Revolutions don't happen over night.