On “The basis of liberal-conservative rapprochement.” In his 1955 book The Public Philosophy, Walter Lippmann points out how progressives need conservatism:

. . . no one generation of men are capable of creating for themselves the arts and sciences of a high civilization. Men can know more than their ancestors did if they start with a knowledge of what their ancestors had already learned. they can do advanced experiments if they do not have to learn all over again how to do the elementary ones. That is why a society can be progressive only if it conserves its traditions. (136)

While Lippmann here uses an example more suited for science or mathematics, the larger context of his claim is political or civil.