Recently I had a conversation about ISIS with a friend who is Catholic by faith, he said that ISIS should be stopped but that we (The US or any other foreign power) should not kill them, whereas I said that things have come to the point of using combat in order to stop them from murdering thousands of innocent people. He backed his claim by saying that both Jews and Christians believe that the use of violence disregards the idea of appreciating the sanctity of life.
I am not a warmonger nor am I anti-Islamic or someone who believes that combat is the always the answer and that as per the Torah, Tanakh, Talmud, and basic moral logic that life is in fact sacred and should be highly valued and in this case to protect innocent lives, killing ISIS soldiers may be necessary in order to stop them from their "conquest".
Also given that a strong majority of Muslims do not believe ISIS actually conforms to Islam and that their actions are plainly barbaric and wrong, is it permissible by Biblical law and reason to use violence against ISIS in order to stop them?
My rebuttal to his claim would be from the Jewish viewpoint so is there any scripture or ruling that I could use to support my view?