Rowan County, Ky. Clerk Kim Davis shows emotion as she...

Rowan County, Ky. Clerk Kim Davis shows emotion as she is cheered by a gathering of supporters during a rally on the steps of the Kentucky State Capitol in Frankfort Ky. The U.S. Supreme Court on Monday, Aug. 31, 2015, ruled against Davis, who has refused to issue same-sex marriage licenses. Credit: AP Photo/Timothy D. Easley, File

What's in an oath?

That fascinating question arose as part of a crusade by Rowan County, Kentucky, Clerk Kim Davis to seek a religious exemption from issuing marriage licenses to gay couples. Before the U.S. Supreme Court put the kibosh on her claim, Davis in her legal brief argued that she understood her oath of office "to mean that, in upholding the federal and state constitutions and laws, she would not act in contradiction to the moral law of God."

Why? Because her oath included the words, "So help me God." Of course, the oath of office prescribed by the U.S. Constitution doesn't include those words. George Washington famously added them after taking the oath of office as president, and tradition has maintained them. Davis's claim, however, is nevertheless intriguing. It implies that obedience to divine law is somehow baked in to one's constitutional duties and obligations.

And Davis, it seems, isn't alone. A few days ago, in response to a column I'd written suggesting that Arkansas's proposed Ten Commandments statue for the grounds of the state capital violates the U.S. Constitution's establishment clause, Arkansas State Senator Jason Rapert tweeted a question to me that seemed like it might be rhetorical. "How is it," he wrote, "you conclude that the federal government can tell state governments what monuments they can or cannot install?" 

I'm not a very skilled or faithful Twitter user. Nevertheless, something about the question struck me, so I wrote back, "It doesn't! The Constitution doesn't. You know, the one you swore to uphold."

Rapert sent me a flurry of counterresponses, but what was most striking was his direct reply to my point about the oath. "Yes," Rapert wrote, "with my right hand on the Bible every- time." 

I confess I wasn't sure what he meant at first -- but when I read about Davis's brief, it clicked. The Arkansas senator was saying, I think, that by putting his hand on the Bible when he swore to uphold the Constitution, he was putting the Bible first. That resonates with Davis's argument that her oath incorporated her faith.

Are Davis and Rapert right about the oath of office? The core of their notion isn't crazy. An oath is typically taken by some power, and most people no doubt believe they're swearing by Almighty God to uphold the Constitution and laws of the United States (and of the state, in the case of these state officials). Would it make sense to swear an oath in God's name and then go and obey that oath in violation of God's word? It wouldn't, of course -- but that's (mostly) beside the point. Whom you swear the oath by is different from what you swear to do. Officials in the U.S. definitively don't swear to uphold God's law. They swear to uphold the Constitution, which never mentions God at all. And they swear to uphold laws enacted under the Constitution -- which means laws that are in compliance with the establishment clause that prohibits any established or official religion.

That's the main reason the framers didn't include God in the oath of office. It would've contradicted the proposition in the Constitution that said no religious test would ever be required to hold office under the Constitution.

Of course, there's nothing wrong with doing like Washington and adding God to the oath. But the key point is that doing so is a personal decision -- not an official or professional one. And the consequence of that distinction is all-important.

It's just fine -- in fact, I think it's admirable -- for a public official to say that he or she won't enforce any law that's fundamentally immoral and in contradiction to God's laws. But the only way to keep that promise consistent with the oath of office is for the official to resign when she thinks enforcing the law would be wrong. Given Davis's statement of faith that it would violate her interpretation of God's will to issue a marriage license to a same-sex couple, she should quit her position as county clerk. Indeed, she must -- or she'd be living in a position of hypocritical sin.

But by saying she won't issue the marriage licenses while serving in office, Davis is also, if I may humbly say so, committing a sin: violating an oath she made before God to uphold the Constitution and laws of the U.S. The Constitution requires her to issue licenses for gay couples. Every moment she disobeys the Constitution, she is violating her oath. The Bible doesn't look kindly on oath-breaking. The only way for her to emerge from the state of sin is to resign.

Under the Constitution, the government can't force you to engage in a religious action or stop you from exercising your freedom of religion. Normally, it shouldn't coerce you to act against your faith. But no one was or is coercing Kim Davis. She's free to serve the public and obey her oath to God to follow the law. And she's free to quit and absolve herself of that oath. The choice is hers.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Before you tell me that the Constitution doesn't require gay marriage, it's just that the Supreme Court says it does, think again. The Supreme Court's interpretation of the Constitution is binding -- and that's a cardinal constitutional principle that can't be denied by anyone who works for any part of the U.S. government. If you don't agree with that, there's a Civil War that needs fighting, again.