Fred Siegel is a professor of history and senior fellow at a centre-left think tank in the US.
In this article for City Journal, he argues the rise of environmentalism has poisoned liberals’ historical optimism:
For the first two-thirds of the twentieth century, American liberals distinguished themselves from conservatives by what Lionel Trilling called “a spiritual orthodoxy of belief in progress.” Liberalism placed its hopes in human perfectibility. Regarding human nature as essentially both beneficent and malleable, liberals, like their socialist cousins, argued that with the aid of science and given the proper social and economic conditions, humanity could free itself from its cramped carapace of greed and distrust and enter a realm of true freedom and happiness. Conservatives, by contrast, clung to a tragic sense of man’s inherent limitations. While acknowledging the benefits of science, they argued that it could never fundamentally reform, let alone transcend, the human condition. Most problems don’t have a solution, the conservatives maintained; rather than attempting Promethean feats, man would do best to find a balanced place in the world.
In the late 1960s, liberals appeared to have the better of the argument. Something approaching the realm of freedom seemed to have arrived. American workers, white and black, achieved hitherto unimagined levels of prosperity. In the nineteenth century, only utopian socialists had imagined that ordinary workers could achieve a degree of leisure; in the 1930s, radicals had insisted that prosperity was unattainable under American capitalism; yet these seemingly unreachable goals were achieved in the two decades after World War II.
Why, then, did American liberalism, starting in the early 1970s, undergo a historic metanoia, dismissing the idea of progress just as progress was being won? Multiple political and economic forces paved liberalism’s path away from its mid-century optimism and toward an aristocratic outlook reminiscent of the Tory Radicalism of nineteenth-century Britain; but one of the most powerful was the rise of the modern environmental movement and its recurrent hysterias.
The full article is a provocative read.