The key theory of the Right is that people are prone to laziness, violence, hysteria, and sin, and that they must be treated with threats, force, and commandments. The right argues that treating people badly is best. The key theory of the Left is that much of what people do that is wrong is out of ignorance, or the response to maltreatment. The left argues that treating people well is best. Across this chasm the left and the right shout at each other.
The rightward drift came as an aging gerontocracy believed that the solution to violent abuse not working, was more violent abuse. The solution to a plutocracy impoverishing the nation, was more plutocracy, the solution to consumption making a sick, was to have more, lower quality, consumption.