Barack Obama, a former law professor, has argued that “What our deliberative, pluralistic democracy demands is that the religiously motivated translate their concerns into universal, rather than religion-specific, values.” Religious motivation is fine; just don’t make your religious views the basis for public policy. But democracy “demands” no such thing. Democracy is a system that adjudicates contending claims. Some prevail over others; all are subject to the Constitution.

In fact, “religion-specific values” have driven the most consequential American political debates for over 200 years. Some make claims about objective moral truths: for example, in the Declaration of Independence (“all men are created equal,” “endowed by their Creator with certain unalienable rights”), abolitionism, women’s suffrage, civil rights laws and discussions of the nature and value of marriage. Others make more particular claims: for example, calling for temperance, withdrawal from Vietnam or a higher minimum wage. In the American system, all religious claims are free to contend. Without them, America would be a very different place.

Which makes the effort to separate the religious and political threads in the American tapestry all the more dangerous. In 2010, the U.S. District Court Judge Vaughn Walker invalidated a California ballot initiative for which millions of religiously motivated blacks and Latinos, among others, had voted on the same day they cast ballots for Barack Obama. The measure was Proposition 8, defining marriage as between a man and a woman. The presence of religious arguments in the campaign led Judge Walker to assert that the “moral and religious views” underpinning the vote were not “rational,” rendering the measure unconstitutional.

Walker’s ruling, like Obama’s assertion, represents a results-oriented effort to expel religious arguments from democratic deliberation. This has been a tempting device for partisans of all stripes. To silence religiously motivated civil rights advocates like Martin Luther King Jr., Jerry Falwell once asserted that “Preachers are not called to be politicians, but soul winners.” Whatever its source, any effort to confine religious people and their ideas to an innocuous spirituality or a merely ceremonial role in public life is a threat to religious liberty and to American democracy.

Religion in the Public Square by Tim Shah is the associate director and Tom Farr, The New York Times