During one of the first major Republican debates in the presidential primary earlier this month in Iowa, Byron York, a journalist for the conservative Washington Examiner, asked Michele Bachmann a question that’s been on many minds but few tongues this summer.

In 2006, when you were running for Congress, you described a moment in your life when your husband said you should study for a degree in tax law. You said you hated the idea, and then you explained: ‘But the Lord said, be submissive. Wives, you are to be submissive to your husband.’ As president, would you be submissive to your husband?

The question drew gasps and boos from the mostly conservative audience, and Bachmann herself at first seemed taken aback by it. She nimbly turned the query into an opportunity to talk about how much she and her husband of almost 33 years love each other. And, in the end, the exchange did more damage to York than to her.

In the week since then, a perennially uncomfortable public debate has emerged over the role of religion and the US presidency, accompanied by a meta-debate over whether Americans — and, in particular, journalists — should even be asking questions about the relationship between the two.

Conventional wisdom says the Republican primary has crystalised over the last week into a race between three candidates who come with intriguing religious story lines: Bachmann, whose particularly Evangelical form of Christianity was the subject of a lengthy (and, to many, alarming) New Yorker profile last week; Mitt Romney, whose Mormon heritage elicited much suspicion during his last run for the job in 2008; and Texas Gov. Rick Perry, who angered atheists by hosting an 8,000-person strong Christian prayer revival two weeks ago in which he asked God to help guide a “nation in crisis” when its politicians have proven unable to do that alone.

NPR characterised Perry’s event as sparking a “holy war” among critics “who claim it [was] Jesus-exclusive and political.” The New Yorker profile of Bachmann, which followed shortly thereafter, upped the ante on the religious alarmism. And then Byron York asked Bachmann, a Tea Party favorite, about her Biblically based beliefs on the “submissive” role of women to their husbands.

Since John F. Kennedy, the first Catholic in the White House, Americans have prided themselves on holding no religious litmus test for the office. The separation of church and state — as central to the American political identity as protections for free speech also enshrined in the First Amendment — means elected officials can’t impose their beliefs on others but also have a right to believe in whatever they want themselves.

Bachmann and Perry, though, have touched a nerve among voters and commentators who aren’t convinced they share that same interpretation of the establishment clause. And in that context, York’s query was extremely relevant.

As the discussion on one popular legal blog put it:

“Rep. Bachmann’s religious beliefs are a mandatory topic for thorough examination and public debate. Why? Because she espouses a brand of Christianity that seeks not merely to transform the institutions of government, but to absorb them into a reconstructed society build upon a foundation of Old Testament law, a goal which implicates the Constitution and which strikes at the heart of the idea of secular government.”

York’s many critics since last week of course will disagree with this. But to suggest that all queries along these lines should be off-limits for the next year — particularly as they relate to politicians who have willingly made such a public show of their private faith — is disingenuous. Yes, Perry and Bachmann have a right guaranteed by the Constitution to follow any faith they chose. But voters and journalists have a right, too, to ask about how that faith will impact a candidate’s positions in office when the evidence thus far suggests that it might. Critics who want to shout down those questioners, claiming offense, stifle an important election-year debate.

Emily Badger is Index on Censorship’s US Editor