Civil resistance is political action that relies on the use of nonviolent resistance by civil groups to challenge a particular power, force, policy or regime. Civil resistance operates through appeals to the adversary, pressure and coercion: it can involve systematic attempts to undermine the adversary's sources of power, both domestic and international. Forms of action have included demonstrations, vigils and petitions; strikes, go-slows, boycotts and emigration movements; and sit-ins, occupations, and the creation of parallel institutions of government. Civil resistance movements' motivations for avoiding violence are generally related to context, including a society's values and its experience of war and violence, rather than to any absolute ethical principle. Cases of civil resistance can be found throughout history and in many modern struggles, against both tyrannical rulers and democratically elected governments. The phenomenon of civil resistance is often associated with the advancement of democracy.