During the Progressive Era, a new theory of justice took hold.
Today, people who call themselves conservatives and liberals alike accept much of the Progressive view of the world.
Although few outside of the academy openly attack the Founders, I know of no prominent politician, and only the tiniest minority of scholars, who altogether support the Founders' principles.
Liberals like Gordon Wood agree, but they think that the change in question is good, not bad.
Wood writes that although the Founders themselves did not understand the implications of the ideas of the Revolution, those ideas eventually "made possible…all our current egalitarian thinking." My own view is this: Although the first two of the three mentioned causes (material circumstances and politicians' self-interest) certainly played a part, the most important cause was a change in the prevailing understanding of justice among leading American intellectuals and, to a lesser extent, in the American people.
Among conservatives, Robert Bork's Slouching Toward Gomorrah adopts the gloomy view that the Founders' devotion to the principles of liberty and equality led inexorably to the excesses of today's welfare state and cultural decay.