Complex sentence: The group believed that violence-or the threat of it-might be needed to bring about social change, and they sometimes made news with a show of force, as they did when they entered the California Legislature fully armed to protest a gun bill.
Split into simpler sentences: The group believed that violence-or the threat of it-might be needed to bring about social change. They sometimes made news with a show of force, as they did when they entered the California Legislature fully armed in order to protest a gun bill.