Not sure ifs been suggesting lets say you have to allies who are not friendly with each other, you give the option for them(or yourself depending) the ability to be able to fight on your territory or not. Im not sure if this is already done but I havent had the situation happen yet. And by whichever one you choose, you get a buff and a debuff.

Ex:

War: to have war allowed on your territory, whatever units get killed in your inventory you get a fraction of the units worth(say 5-10-25%-ish), but culture in your area is lowered.

Anti-war: To prohibit war in your territory, you get a boost in culture in your empire as a whole(The farther the smaller the boost), but you do not get the fraction of the units worth.