DOES THE CIVIL WAR ENDED IN USA?

I was sitting with a Canadian couple last month while our cenversation turn to the on-going wars in various part of the world , especially in Syria which affecting us (Turkey) very badly nowadays.

I said them that I am having difficulties in understanding USA , Russia , China and Iran activities (any many other countries) in other countries .What a bad remembrance we have in Korea , Vietnam , Afganistan , Irak , Libya , Lebanon and now on stage in Syria and Yemen . How come that these countries deliberately pursue activity in other -weak an unstable countries. 

Why USA , Russia and Iran are playing various games in Syria by proxy armies and mercenaries?

As an outsider most of the world think that USA is one single country. So were thoughts for the Soviet Union before the downfall of Berliner Wall. We think that EU was established with a goodwill of the participant countries. We mostly and frequently forget the hundred million innocent deaths in WW1and WW2 . 

Countries who fighted each other for long time , destroying each other severy set out over a table to established (EU)  a long lasting peace treaty by reducing the economic gap in between , opening the borders for people -not only  to travel but also to work , transfer their capital freely and trade freely without counterwailing taxes to protect a sole country citizens.

Soviet Union was a different version of it. But the management couln't not steer the country good enough by reducing the economical differences in its territories.

USA is also a large group of countries incorporated after long lasting deadly civil war. My Canadian friend told me that the civil war in USA did not finish. USA has the largest amount of weaponary in hand of its citizens, at home. USA murder and crime is highest in the world. Kennedy's and Luter King assasinations were not coincidal.

As a Turk I do not pretend that our policy was right until now, but now a war became unavoidable in the northern part of Syria.