Yes, there are examples showing that violent action is ineffective, and one example is the Crusades. Another example would be the U.S. action in Vietnam. Another example would be the actions of the perpetrators of September 11, 2001. Violence to make people believe a certain point of view is seldom effective. Words are more persuasive.
Both the Vietnam War and Iraq War in United States history caused more civilian casualties than they prevented. Communism in Vietnam would have died eventually, just as the Soviet Union did in the early 1990s. Saddam Hussein would have been overthrown eventually. Violence during Iran's elections in 2009 also proved ineffective as social media caused international firestorms with videos leaked from Iran, despite Mahmoud Ahmadinejad's attempts to stifle freedom of expression and freedom of the media in his country. Violence only begets more violence and doesn't solve anything. Words followed by action are what moves the human condition.