Pete Buttigieg, the mayor of South Bend, Ind., is one of the many candidates for the Democratic presidential nomination. But that’s not his only long-shot bid. He also wants to claim Christianity for contemporary progressive politics.

“Christian faith is going to point you in a progressive direction,” he told USA Today.

Even in our largely secular press, the coverage of the Buttigieg campaign has been rapturous. A few conservatives have contested the mayor’s version of religious politics by denying that he is truly Christian, citing his support for same-sex marriage (he is in one) and legal third-trimester abortion. Some of those critics have gone so far as to dismiss the Episcopal church, of which the mayor is a member, as no longer Christian.

Buttigieg’s fans have, naturally, responded to that line of argument with outrage, having apparently missed that the mayor is fine with questioning another person’s faith. “It is hard to look at this president's actions and believe that they’re the actions of somebody who believes in God,” he said in that USA Today interview.

Obviously, people who describe themselves as “Christians” disagree with one another, generally sincerely, about what being a Christian entails. There are Protestants who don’t think that Catholics make the cut.

For Buttigieg, the basic mistake of conservative Christians is “saying so much about what Christ said so little about, and so little about what he said so much about.” His interviewer, journalist Kirsten Powers, calls it an “insightful formulation” and specifies that abortion is one of those topics Jesus ignored.

What He did talk about, Buttigieg says, includes “defending the poor, and the immigrant, and the stranger, and the prisoner, and the outcast, and those who are left behind by the way society works.” Hence his claim about how Christianity dovetails with progressivism.

It is a heartfelt argument. It is also partisan nonsense, a politicized distortion of both the Bible’s words and its silences. Consider that the argument could just as easily be, and was, deployed against William Wilberforce and other Christian abolitionists. Notoriously, the Bible nowhere explicitly condemns slavery.

There is room for argument among people of good will about the judgments that liberals have reached, as there is room for argument over conservative Christians’ beliefs about abortion. But the idea that unborn children deserve legal protection seems a better fit with the Christian emphasis on mercy than Buttigieg’s cavalier dismissal of it.

Christians should in general be wary of claims that the faith points in a progressive direction, or in the direction of conservatism, toward libertarianism or any other political philosophy or ideology. No political party has ever fully captured the implications of Christianity, and we are not promised that one ever will. As such, no earthly political party or ideology should ever command a Christian’s ultimate allegiance.

Ramesh Ponnuru is a Bloomberg Opinion columnist.