The best method to establish lasting peace is non-violence method or to make a peace treaty between the two conflicting parties or countries.
Step-by-step explanation:
A peace making treaty is the agreeable points over the conflict topics between the two conflicting parties or countries which let them to sage war or fight with one another.
Peace making treaty or any such kind of treaty, upon which both the conflicting parties agrees to, is the most successful method to achieve peace as it brings up the middle path for both of them, and as the issue gets resolved, there is no need for any one of them to go on fight with the other. Hence the lasting peace is achieved.