My father died because he believed in a higher cause, and supported our government. At the time, our government believed it was in our best interests to prevent Vietnam from becoming Communist. You can argue this was a valid goal, although you would have to take a long look at the history of Vietnam to have a proper discussion.
What happened with Vietnam had a massive effect on our society here in the United States. Our military and the support for our military was at it's lowest point ever both from a moral standpoint as well as fighting ability. The general population hated the government, the politicians, and the military. The military itself had crumbled; Officers had no control over the men in their unit and were afraid to enter the barracks. There is a great book about this called the Long Gray Line - It details the Army West Point Class of 1966, their training, Vietnam, and the aftermath and how it effected their lives.
Our military has changed a lot since then. Take a good look at what happened in Iraq - twice. To put it in perspective, The Iraq - Iran war lasted eight years, hundreds of thousands died, and it ended in a stalemate. The United States went in and destroyed the Iranian military and their government in weeks.
Something very similar happened with the Soviet Union with Afghanistan. (I don't know much about it but I just ordered a book off of Amazon.)
It's difficult to compare the Russian military to the American military. Russia doesn't even have a blue water navy. It's only aircraft carrier, the Admiral Kuznetsov, isn't nuclear powered, and recently sailed around Europe to the Mediterranean which was, well, comical. The only aircraft carrier is in such poor shape it had to be freaking towed to Syria.
