What was the long term legacy of the vietnam war

Just so you get an answer that is one, I'll give a brief answer to what I think the legacy of Vietnam was. 

First of all, going to war for most Americans, is not a slam dunk. People (especially in the middle and upper classes), are not enthusiastic about seeing their children come back in body bags. 

And yet ... 

Even as I say this, America has gone into Iraq twice and fought an interminable war in Afghanistan. But had the victories not been quick and overwhelming, America would soon have lost interest. War now is not measured in terms of the time it takes an enemy to surrender. It is measured in how long a country must be occupied. Most of modern debt was accumulated by war.

The cost of the Vietnam war was finally paid off in 2011 about, although no one really realizes that because other wars have accumulated costs of their own. President Johnson was wrong. You cannot have both guns and butter. 

Because he knew the cost of war, Clinton kept America out of any major conflict. Clinton emphasized domestic solutions to the problems America had.