Stay or Go?

Should one stay in churches that affirm beliefs and behaviors that stand opposed to the cross of Christ? Should we remain in such an association in order to work against their delusions and possibly help them change course?

It probably depends on the matter in question, but for those who are deciding what to do in the face of today's watershed theological and social issues, I like Dietrich Bonhoeffer's answer: “If you board the wrong train, it is no use running along the corridor in the opposite direction.”