The Vietnam War

In A Nutshell

The Vietnam War—commonly referred to as "America's longest war"—grew out of the American commitment [Einsatz] to the containment [Zurückdrängen] of communism during the Cold War. For approximately fifteen years, the Democratic Republic of Vietnam (North Vietnam) fought against an American-supported Republic of Vietnam (South Vietnam). The war for the U.S. ended in 1973 with the withdrawal [Rückzug] of American combat troops, and two years later, South Vietnamese forces surrendered to the North [ergaben sich].
With the unification of Vietnam under the Communist government of the North, the U.S. had officially failed to achieve its objectives [Ziele]. A nation accustomed to grand victories suffered its first major defeat [Niederlage]; the "longest war" was a military, political, and social disaster.[Katastrofe] one that would haunt Americans for decades.

Why Should I Care?

What do you imagine when you think of "The Sixties"? Music festivals, "free love," and various drugs, perhaps? Maybe sit-in demonstrations, marches andvery colorful—fashion?
This period in American history is certainly characterized by all of these things, and more often than not it is with these images that Americans today prefer to remember it. And why not? Nostalgia for "The Sixties" gave us poetry slams, retro Volkswagen Beetles, the film Across the Universe, big hoop earringsand Austin Powers. But the event, more than any other, that dominated this decade ( ̴ 1963 to 1973) is the same event that many would prefer to forget—the Vietnam War.
"Nam." In the United States, this one-syllable word has come to mean many things for many different people with various class, racial, political, and national backgrounds. This tiny word carries tremendous weight; it can incite a lot of feelings, including sorrow, regret, anger, revulsion, embarrassment, betrayal [Verrat], and confusion. Many would rather forget it altogether, particularly those who think of this war as one of—if not the—most disastrous [katastrofal] periods in American history.
And Vietnam was, in fact, a monumental catastrophe. But not simply because it was the first major loss for the U.S., and not simply because the U.S. failed to defeat Communism—its most despised [verachtet] enemy during the Cold War. The Vietnam War, a conflict that lasted approximately fifteen years (far longer than any other war fought by the U.S.), was a political, economic, and military nightmare all along the way. And the mistakes made, lies told, and lives lost continue to haunt Americans today, in obvious and not-so-obvious ways.

source: (slightly adapted)