Vietnam was a war we could have won in 1945-46. Ho Chi Minh had no desire to be a puppet of Stalin and the Soviet Union, and offered the United States an opportunity to help set up a Tito-like regime in Indochina, not aligned with either bloc. We refused his offer, and tried to force a return of French colonialism to the region. When that failed in 1954, the Geneva Accords split French Indochina into its component parts--Laos, Cambodia, and Vietnam--and then divided Vietnam into a Communist controlled North, and a very corrupt, despotic, capitalist South.
Over the next ten years, we became increasingly mired in the war in Indochina, starting with covert CIA operations that had actually begun long before the French withdrew. This involvement slowly escalated until the false flag operation involving destroyers USS Turner Joy and USS Maddox took place in August, 1964. This incident resulted in the Gulf of Tonkin Resolution and the beginning of direct, open American military involvement in Vietnam.
Nine years later, the United States withdrew from the war in Vietnam in a negotiated settlement. This war should have taught us the lesson that the Assyrians had learned in Babylon and the Romans had learned in Judea: you cannot force another people to submit to your complete political domination unless you are willing to commit quasi-genocide and scatter the survivors throughout your empire as an object lesson. All of the North Vietnamese and Viet Cong leaders and soldiers who were interviewed after the war were unanimous in stating that they were willing to fight the Americans for thirty years, if that was how long it took to drive us from their country. There was no way to defeat that level of commitment other than genocide.
Our last resolved war had an alliance that was almost unique in world history. The forces in Gulf War I (or Operation Desert Storm if you prefer), that drove Saddam Hussein from Kuwait in 1991 was a joining of both long-time friends and foes against a common enemy. The only similar occurrence in history I can think of--off of the top of my head--was the alliance of Romans, Visigoths, and Franks under Flavius Aetius, who defeated Attila the Hun at Chalons in 451 C.E. But even our success in Gulf War I did not lead to the immediate military destruction of Iraq or the deposing of Saddam Hussein. And it ended with a stringent, but negotiated peace, not an imposed surrender.
So, what is my point, you ask?
First, almost none of the wars that the United States has fought over the last 233 years have ended in a complete, unmitigated victory for this country, in spite of what ignorant fools on the right seem to think. Usually, we are negotiating a peace at the end of one of our wars, not dictating a surrender. In fact, looked at in that light, only the Indian Wars and the Second World War ended with a peace that was dictated by the American government to a prostrate foe, without negotiation.
Second, the utter failure of our Congress to actually declare war in almost seventy years, makes me ask a question: Why?
I think that Marine Major General Smedley Butler gave us the answer seventy-five years ago in a little booklet he wrote called War is a Racket. Here are some excerpts"
"WAR is a racket. It always has been."