Over the years in ministry I have seen good churches go bad. It starts with a false teacher coming in and is popular with the people. After a while a click develops and there is mounting pressure on the pastor or elder to change. From their people become dissatisfied and either they leave, kick the pastor out, change the constitution or force the leadership to resign. False doctrine is like leaven in the bread. 1 Corinthians 5:6 , Matthew 16:6.