Charles J. Chaput, Strangers in a Strange Land: Living the Catholic Faith in a Post-Christian World (2017), Chapter 1, "Resident Aliens" (comments mine):
In a democracy, political legitimacy comes from the will of sovereign individuals. Their will is expressed through elected representatives. Anything that interferes with their will, anything that places inherited or unchosen obligations on the individual -- except for the government itself -- becomes the target of suspicion. [Which is why the Principle of Subsidiarity articulated by Pope Pius XI in Quadragesimo anno (1931) is so important, like the Kuyperian concept of Sphere Sovereignty of 'Intermediary Institutions.']
To protect the sovereignty of individuals, democracy separates them from one another. And to achieve that, the state sooner or later seeks to break down any relationship or entity that stands in its way. That includes every kind of mediating institution, from fraternal organizations to synagogues and churches, to the family itself. This is why Alexis de Tocqueville, the great French observer of early American life, said that "despotism, which is dangerous at all times, [is] particularly to be feared in democratic centuries."
Tocqueville saw that the strength of American society, the force that kept the tyrannical logic of democracy in creative check, was the prevalence and intensity of religious belief. Religion is to democracy as a bridle is to a horse. Religion moderates democracy because it appeals to an authority higher than democracy itself.
But religion only works its influence on democracy if people really believe what it teaches. Nobody believes in God just because it's socially useful. To put it in Catholic terms, Christianity is worthless as a leaven in society unless people actually believe in Jesus Christ, follow the Gospel, love the Church, and act like real disciples. If they don't, then religion is just another form of self-medication. And unfortunately, that's how many of us live out our Baptism.
Until recent decades, American culture was largely Protestant. That was part of the country's genius. But it also meant that Catholics and other minorities lived through long periods of exclusion and prejudice. The effect of being outsiders has always fueled a Catholic passion to fit in, to find a way into the mainstream, to excel by the standards of the people who disdain us. Over time, we Catholics have succeeded very well -- evidently too well. And that very success has weakened any chance the Church had to seize a "Catholic moment" when Catholics might fill the moral hole in our culture created by the collapse of a Protestant consensus.
As a result, Tocqueville's fear about democracy without religious constraints -- what he called its power to kill souls and prepare citizens for servitude -- is arguably where we find ourselves today...."