What was the liberal consensus, and how do you explain the relative decline in liberalism and rise in conservatism during this period?

In the 1950s, most Americans apparently subscribed to the “liberal consensus” about American society. By the 1970s, however, a conservative renaissance was in full swing, and Americans twice elected conservative Ronald Reagan president in the 1980s. What was the liberal consensus, and how do you explain the relative decline in liberalism and rise in conservatism during this period?