Learned through experience
The first of the three, being the RIGHT thing, is a very important lesson that is learned from the post-World War II era. As a result of people doing the wrong thing (such as fighting without a cause in Vietnam), protests form and govenment and citizens collide. These riots are something that is wrong, as loss of life has its inherent immoralities. This can be applied to the post cold war era in that whatever decisions are made with regards to nuclear weapons, they must be decisions to do the RIGHT thing.
Equality is another main lesson that must be remembered. Should equality of all citizens, regardless of race, not be honored, problems arise. The oppressed rise in revolt, and race riots occurred. These can be avoided by honoring equality, and making sure that no repeats of similar incidents to the Rodney King beating happen. Thus, the United States citizens feel more equal, and there are less problems.
The final major lesson that can be identified from the Post World-War II era is that of remembering that people are behind the movements and weapons. People deserve fair treatment, and deserve to have rights. When they stand up for what they believe in, and are in combat with police, their rights still must be recognized. Also, when people are rioting, they must remember that there are people behind the police uniforms as well. Also, as in the case of the Vietnam war, the government must remember that it is sending America's youth, real, live, breathing people, not just statistics, over to fight on foreign soil. These lessons can be integrated into the way that the post-Cold War era is handled.
Through the three lessons of doing the right thing, honoring equality, and remembering the people behind the movements and weapons, valuable knowledge is gained that will help America from repeating the blemished parts of its history.