Well sometimes it might be necessary but this being used as excuse by America , west and even Russia as in case of crimea and Pakistan interference in kashmir ( which failed) I think this idea should be dropped all together in This world. Actually the truth is the decision that one is a dictator or not just depends on self interest of Invading country. Just look at cuba batista was not a dictator to America because it was their dictator while castro is because he nationalized assets which America thought is belonged to it as cuba were her private property. Same with saddam . Who determines one is actually a dictator or not? West have disqualified elected representatives on basis of rigged polls while happily dealt with generals and despots. So this idea is very dangerous. NO country has right to interfere and facilitate regime changes. If there is a problem to world peace then approach U.N and If there is problem with U.N dealing this things then things should be first improved there.