It does no such thing. Once the Supreme Court, Congress and the Executive branch get together politically there is nothing stopping them. All that is needed is a bunch of people that think one party is politically correct and the other party is bad and should be destroyed at any cost. All it takes is a bunch of people that think controversy is bad and should be eliminated. All it takes is a bunch of people that get paid benefits for voting a specific way. All it takes is a bunch of people that don't want to listed to the other side. All it takes is for laws to be enforced based on political affiliation instead of right or wrong. We are already at the point of failure according to the founders, the point where people realize they can vote themselves money from the general fund. Read a little world history.
You do remember that Hitler was democratically elected and was forced to enact laws to protect Germany and certain helpless German citizens. The people willing gave him power and once he became all powerful he was not stoppable without massive bloodshed. World War is what results from too much government power. You want to stop war, then limit government power. It has worked for 100s of years. Weak governments do not make war.