Peace is exhausted when massive protests, large strikes, and large outcry is unheard. Once we have mobilized and made demands to the government which they will not comply with even with our numbers... the time has come.
Peace is not an over-idealistic philosophy either. Many LARGE changes have happened via peace. However, peace is absolutely ended when others strike upon you, so violence is justified when violence is brought to you unprovoked. Many say this is the capitalist wage-enslavement that justifies it, and I'm not so sure I disagree.
He who was previously the money-owner now strides out in front as a capitalist; the possessor of labour-power follows as his worker. The one smirks self-importantly and is intent on business; the other is timid and holds back, like someone who has brought his own hide to market and now has nothing else to expect but - a good tanning. - Karl Marx, Capital Volume I