In the decades that have passed since Vietnam, every responsible American has admitted it was a mistake- but none have thanked the protesters who sparked the discussion and kept the controversy alive, finally leading to withdrawal.
In fact, in the agony of "defeat", America turned on the 'dope smoking hippies' who dissented, and for the past 40 years has been throwing them in jail for smoking dope. In the process, huge social catastrophes, huge budget deficits, and the total erosion of our liberties have occurred.
It now seems that legalization will only occur when a majority of the people think of Vietnam as "history", and view prohibition in terms of whether it makes sense- at which point, prohibition will end.
For a few years those flower-power hippies were a thin line between the USA and a yawning chasm of moral and fiscal bankruptcy. The war on marijuana remains as an ongoing campaign against human rights and fiscal sobriety. It's time to call a halt.