TDL put the issue very well, the UN and Nato or the Russians or the AU, any of the peacekeeping organizations operate on the hospitality of the countries they are deployed to. Without the approval of the country in question they cannot be deployed, and even after they are deployed the host country can ask them to leave at any time and they have no choice but to comply. For example, in 1967 on the eve of the Six Day War, the Egyptians and Syrians asked the UN peacekeepers deployed along the Suez canal and the Golan Heights to leave, and of course, they had no option but to leave. If you operate against the houses in attempting to stop war, you will end up fighting on the side of the losing side, because the side that is winning has no incentive to allow you to operate.