If we would have stayed in Vietnam long enough we could have killed enough people to win the war. Same as Iraq however in order for us to to win that war Pakistan is going to have to crack down on the Taliban and Al Qaeda which I don't see happening anytime soon.
Although the Vietnam War did not achieve it's overall goal it did have some accomplishments. The military of North Vietnam had been improved, enabling it to defend itself against neighboring countries such as Cambodia and Red China. The war also introduced Eastern Culture to Western ways, laws, and trade practices that helped it to enter the world of trade and commercialism in the 21st Century.