No countries should interfere in any other country's internal trouble
We cannot forget the Vietnam War, which continued for 21 years.
Ho Chi Minh, the Vietnam independence movement leader, tried to use Communism just for the independence. The ostensible reason of French and US interfere was to relieve the Vietnamese people from the evil of Communism, but their interference, in fact, only tortured the people for a long time.
The Meiji Restoration, the Japanese modernization in 1868,succeeded in terminating the 650 year feudal period by a two-year civil war because they removed British, French and US interference. On the other hand, almost at the same time some Chinese dukes put British and French militaries to use for suppression of rebellion. The result was that China became a kind of colony of both countries, which continued from the latter 19 century to the middle of 20 century, and the Chinese people suffered serious pain. There is no foreign interference without merits for the home country.
Here is another example in the former Yugoslavia. Because Slovenia and Croatia fought for and won their own independence, the war ended within a year. Bosnia Herzegovina took a long time to become independent since foreign countries interfered. If a foreign country helps one side, another country will help the other side. And also foreign countries bring modern weapons to a conflict. In the former Yugoslavia case, the European Union helped Bosnia Herzegovina whereas Russia supported Serbia. Both sides made many air raids in terms of keeping their own soldiers (but not the local people) from death although there was no air force in this country. That's the reason foreign interference makes conflict complicated and prolonged.
People should settle domestic problems by themselves even though they are difficult and trying. At first sight it seems that foreign interference and modern weapons help those people, but it is just an illusion. Even though interference is put into practice to prevent genocide, every interfering country always care about the home country's interests. No countries help others just because of kindness. Moreover, interference does not always help interfering countries like the Vietnam War. I hope that all countries will understand this concept and not interfere in other's conflict. Interference just harms both interfering countries and interfered countries. No countries should interfere in any other country's internal trouble.