Secular liberalism is a religion with fully fundamentalist adherents, just as Christianity is. So says self-described liberal, formerly of First Things, Damon Linker:
From the dawn of the modern age, religious thinkers have warned that, strictly speaking, secular politics is impossible — that without the transcendent foundation of Judeo-Christian monotheism to limit the political sphere, ostensibly secular citizens would begin to invest political ideas and ideologies with transcendent, theological meaning.
Put somewhat differently: Human beings will be religious one way or another. Either they will be religious about religious things, or they will be religious about political things.
With traditional faith in rapid retreat over the past decade, liberals have begun to grow increasingly religious about their own liberalism, which they are treating as a comprehensive view of reality and the human good.
But liberalism’s leading theoreticians (Locke, Montesquieu, Jefferson, Madison, Tocqueville, Mill) never intended it to serve as a comprehensive view of reality and the human good. On the contrary, liberalism was supposed to act as a narrowly political strategy for living peacefully in a world of inexorably clashing comprehensive views of reality and the human good.