Of all the scandals that have come to light with the internal communications of Secretary Clinton’s campaign, the most startling is the degree to which it has been infected by what could be called liberal supersessionism. Classical supersessionism is the notion that Judaism has been superseded by Christianity. “Supersessionism, in its more radical form,” according to the Christian Web site Theopedia, “maintains that the Jews are no longer considered to be God’s Chosen people in any sense.”

This idea has been in retreat in recent years, with Pope Francis going so far as to call for an end to evangelization of Jews. What, though, are we to make of the emergence of the idea that secular liberalism supersedes all religious doctrine and is even superior to it? This is showing up in, among other places, the email messages in respect of Catholics that went back and forth among of members of Mrs. Clinton’s campaign camarilla, including her chairman, John Podesta.

One of the emails complains about how “Friggin’ Murdoch” had his children baptized where, according to the Christian Bible, John baptized Jesus. That cable is from John Halpin of the Center for American “Progress.” Mr. Halpin complains that “many of the most powerful elements of the conservative movement are all Catholic (many converts),” from the Supreme Court “and think tanks to the media and social groups.” They “must be attracted,” he speculates, to Catholicism’s “systematic thought and severely backwards gender relations.”

Notice in respect of the Supreme Court the glancing religious test (it has long since crept in to the Democratic critique of the high bench). The emails among Mrs. Clinton’s campaign intelligentsia also include a wire from the president of a group called Voices for Progress, Sandy Newman, discussing the idea of fomenting a “Catholic Spring, in which Catholics themselves demand the end of a middle ages dictatorship and the beginning of a little democracy and respect for gender equality in the Catholic church.”

Mr. Newman writes that he worries about his own “total lack of understanding of the Catholic church, the economic power it can bring to bear against nuns and priests.” Does he imagine that, say, the Little Sisters of the Poor would just love to purchase birth control insurance for their employees were but the dictators in Rome prepared to permit it? It’s for the rest of us a glimpse of how progressives think of themselves as the new chosen people. They are chosen not by God — Heaven forfend — but by themselves.

Then again, too, that would be fine were it not for the lunge for the political — meaning state — power that the Democrats are preparing to use against religious Americans in the new secular age. We didn’t start out our long newspaper career expecting to be ringing this alarm 50 years later. But that’s where the story has taken us in the 21st century. The biggest problem with the Democratic Party today is not its liberalism but its illiberalism, born of a secular supersessionism that has run amok.