One of the illusions of modernist thinking is that religious beliefs can be sanitized and separated from public life. The experience of humanity disproves that theory, but it nevertheless remains something of a sacred precept within the intellectual elites — a sector of society most prone to believing that religious convictions ultimately do not matter.

Last week, on the 50th anniversary of his speech, I argued once again against the position taken by John F. Kennedy when he spoke to a gathering of ministers during the 1960 presidential race. Sen. Kennedy spoke eloquently about his hope that his religious beliefs would be a private matter and his affirmation that he would keep them so. [See my article here.] This was a pledge that could be made only by someone who would straightforwardly say that his faith was not, in essence, a significant part of his intellectual framework.

In general, the political Left has tenaciously held to the Kennedy formula. But next week a book appears that might well reset that equation. Writing from the political Left, Damon Linker argues that religious convictions do matter — and matter a great deal.

His new book, The Religious Test: Why We Must Question the Beliefs of Our Leaders, is due out next week. We can gain a taste of what is coming through a major opinion piece he contributed to Sunday’s edition of The Washington Post.

Here is a crucial excerpt:

Every religion is radically particular, with its own distinctive beliefs about God, human history and the world. These are specific, concrete claims — about the status of the religious community in relation to other groups and to the nation as a whole, about the character of political and divine authority, about the place of prophecy in religious and political life, about the scope of human knowledge, about the providential role of God in human history, and about the moral and legal status of sex. Depending on where believers come down on such issues, their faith may or may not clash with the requirements of democratic politics.

That is a classic paragraph that will be hard for anyone to refute — unless you still believe that religion and public life can be neatly divided.

Now, Linker calls for the deregulation of sexual morality, and these controversial issues frame the urgency of his argument. I will take a closer look at his book next week.