There is a video clip of Rav Shach ZT”L speaking when the Degel party was launched. He emphatically stated that אלימות is not acceptable, and that all behavior needs to be like bnei Torah. He also said openly that anyone engaging in אלימות should be reported to police. And he was addressing his own agenda for politics, clearly a “just cause” for him, yet he admonished against sinking to the level of behaving violently and offensively.
It might be a good idea to locate the clip and post it on YWN.