Before public opinion turned against the war by the late 1960s, why didn't the US ever just invade North Vietnam?
Since the NVA was never a match for the US military (unlike the Red Army) it would have to be due to the lack of political will by the Johnson administration. My question is why wasn't the will there when the solution to winning the war was obvious (invade/occupy the North, depose their government and destroy the NVA entirely)?