Prabhupada: These wars where the demons fight the demons they don't mean anything because just the demons win. But if you have a war where one side there are devotees and the other side demons then its Krishna Conscious. Then its Krishna Conscious. First you say "No. No. No. And finally .. a slap on the hand."
Ravindra-svarupa das: You envision a time when the Krishna Conscious devotees will command armies and run whole countries. How can we be sure, under those circumstances, that we won't become demons?
Prabhupada: Chant sixteen rounds a day and follow the four regulative principles.
Ravindra-svarupa das: That's enough?
Prabhupada: That's enough.
This is sourced from a seminar entitled 'ISKCON – The enemy within' by His Grace Ravindra-svarupa Prabhu.
Many more lectures from Ravindra-svarupa Prabhu are here.