In Navadvipa all the learned scholars are followers of the smrti-sastra, and Lord Caitanya Mahaprabhu did not attempt to convert them. Therefore the author has remarked that the spiritual potency Lord Sri Caitanya Mahaprabhu did not manifest at Navadvipa was by His grace manifested in South India. Thus everyone there became a Vaisnava. By this it is to be understood that people are really interested in preaching in a favorable situation. If the candidates for conversion are too disturbing, a preacher may not attempt to spread Krsna consciousness amongst them. It is better to go where the situation is more favorable. This Krsna consciousness movement was first attempted in India, but the people of India, being absorbed in political thoughts, did not take to it. They were entranced by the political leaders. We preferred, therefore, to come to the West, following the order of our spiritual master, and by the grace of Lord Caitanya Mahaprabhu this movement is becoming successful.

From Srila Prabhupada's purport to Cc Madhya 7.109.