Actually, we made a deal with the French, who were already inside VietNam: We would replace French "advisers" with American "advisers" if France would join NATO. The biggest mistake with VietNam is that once there and entrenched for years, we were not allowed to actually win the war, which destroyed most of our VietNamese allies. Overall, VietNam was one of the biggest failures in our history.
I'm not going to say slavery, because we are talking about centuries back, when the culture of slavery along with indentured servitude was common throughout most of the world. The Civil War was not really a failure, because it focused on the brutality of slavery and the actual "process" of owning another human being. I'm disappointed that a century later, entrenched institutionalized racism had still not been recognized as wrong in too many parts of the country. Fifty years later, I'm pleased with the progress that has been made.
Most recent failures are first, a pre-emptive invasion of Iraq based upon deceit and worthless intelligence, along with a decades-long occupation that allowed rival tribes and outside forces to create what will no doubt soon be their own civil war.
Second, a botched invasion into Afghanistan, which should have ended in a matter of months at Tora Bora, but didn't because the administration withheld the troops necessary to have surrounded and defeated the Taliban/Al Qaeda in order to have enough resources to later invade Iraq. Then, instead of admitting we screwed up, we proceeded to occupy the country for a decade, allowing the Taliban to rebuild and retake the country the minute we are gone.
We've had a lot of failures over the two centuries of our existance. The only ones that shame me is how long it took for Civil Rights and Equality to be implemented after the Civil War, the treatment of American Indians during the Indian Wars... and the invasion of Iraq.
