Basically, you're going to want to anger the militarists as much as possible. Start a sandbox game with unlimited money, then fortify your palace by buying the 4 more guards upgrade and filling all the slots.
Next, build a barracks, and then build a ton of buildings that the militarists don't like. (embassies work great) Quick build like 20 of them, and you should receive a militarists ultimatum. Deny their demand, and they should stage a coup. They should be weak enough for your palace guards to easily kill them off. Once they've done so, the trophy is yours.