Large government. Racism. Race baiting. Feminism. Male rights advocacy. Truthers of all kinds. Certain welfare programs. War. Nuclear weapons. I could do this all day. XD
Large governments are a constant of history, shifting from place to place, according to sociogeopolitical dynamics (damn, I think I came up with a new word!)
Constants tend to be inevitable, and a symptom of our species
Racism are a constant of history, if you not only count America, and begin to systematically count racism around the world, including institutionalized racism, you will discover that it is as common as it has always been - only shifted around a bit.
Female role in society has always been contested. The Amazone legends are an example of how ancient this push-and-shove situation is. Religion plays a huge role. In pagan viking society women were perfectly welcome to fight side by side with male warriors, the term "shield-maiden" being common. Women also held all property keys in a bag on their belt, and were therefore the practical masters of the house, controlling when the door is open or shut. However, women are the only gender who can give birth, and in order for populations not to stagnate, society depends on women - at least for the duration of toddler-raising - tends to birthing and raising the toddler. This is pretty much what a modern democratic society tries to do. The struggle, however, is still there -
especially if you count the rest of the world, where women are still sold as cattle, in certain societies. As long as the genders will never become identical, the struggle will remain part of human nature - however with the destruction of arbitrary religions and traditions, the impact of it can be minimized.
Truthers always existed, because people are imaginative - and information is withheld from them, almost always in the posession of others, and distributed in portions. People on earth have an inherent knowledge that any statement might be true or false. We ultimately have to go by probability, and the human brain struggles particularily with predicting probability (instead relying on patterns of recognition and association).
And war? Well... War never changes.