Even though we fought in different wars, at different times, we all fought for the same thing. Our freedom as Americans.
After WW2, the USA and Russia were the world powers. Of course, when there is power, there is competition. Them both being so powerful created a power struggle that has lasted to this day.
All the way across the ocean, wars were breaking out, and we felt it was our duty to help out in the way that benefited us the most. These actions made Russia get involved, because we were sending large amounts of troops near their border.
Vietnam and Korea were both wars where the US was trying to prevent the spread of communism, and both countries split up in the process.
Vietnam ended with the capture of Saigon, and Vietnam reunified after the ending and stayed communist.
Korean war ¨ended¨ with a cease fire, and stayed separated after the end.