Evangelical churches long have been called the Republican Party at prayer. The observation might be close to true in Iowa. And that should make American Christians nervous about their future in politics.

The relationship of religion and politics has been fraught with controversy since America’s founding. In Europe a brutal mixture of church and state harmed both institutions: faith was perverted by power, sometimes using and sometimes used by the state. The Founders opposed a similar practice in America, hence the First Amendment’s ban on the “establishment” of religion.

At the same time, the new nation included people who fled religious persecution elsewhere and for whom obedience to God superseded obedience to king. To ensure their ability to practice their faith, including to be “salt and light” in the larger society, the Constitution guarantees religion’s “free exercise.”

However, the Founders did not want to see a republic divided along religious lines. Not only did the Constitution bar any religious test, but the early leaders were a motley crew when it came to matters of faith. Serious Christians were active at all levels of society, but the Founders were not an especially devout lot. Even George Washington, so revered by so many, probably was a deist despite his shows of public piety.

Yet today some Christian activists seek a Christian candidate. TV personality Jim Bob Duggar urged Iowans to vote for Rick Santorum: “We are asking all the Christians throughout America to get behind him so we can have a godly Christian man as president.”

Not a competent, smart, effective president. Not a realistic, thoughtful, or even principled president. Not a president with good policy answers for big questions, such as economic growth, international conflict, and social division. Just “a godly Christian man.”

For some Iowa evangelicals, at least, that appears to be a narrow category. It obviously does not include President Barack Obama, who professes to be “a godly Christian man.” Nor do many others apparently qualify.

The Washington Post profiled one family who chose Santorum as essentially the last man standing. Michele Bachmann was unacceptable because she was a woman, even though the Bible does not bar women from political office. Mitt Romney was unacceptable because he was a Mormon, even though God does not restrict who can serve as a civil magistrate.

Newt Gingrich was unacceptable because of his serial adultery, even though the Apostle Paul emphasized maintaining moral purity within the community of faith (“What business is it of mine to judge those outside the church?”, 1 Cor. 5: 12). Ron Paul was unacceptable because he did not favor promiscuous war-making, even though Jesus is the Prince of Peace. (Really, the Bible does not say “kill a foreigner for Christ.”) Only Rick Perry, it seemed, was dismissed for mundane political reasons: an inadequate understanding of the issues.

That’s quite a list. And these Iowans were not the only ones to cite Romney’s Mormonism. Another one told the Washington Post: “Everyone needs to base their decision on something, and the basis for his decisions would be different. I’m not convinced it’s a good point of view to be coming from.” A couple friends in my evangelical church in northern Virginia believe similarly.

Yet this confuses civil and religious office.

No doubt, there is a certain personal satisfaction in having someone like one serve as president. But surely the most important qualification for the office is the capability to fulfill the duties of the office.

Imagine a godly man likely to consistently expand government power, sacrificing civil liberties, increasing federal spending, and promiscuously intervening abroad. (Imagine George W. Bush!) The result would be (and was!) less liberty, wealth, and peace. These policies do not become more palatable if implemented by a devout, God-fearing person. Give me the lovable rogue — even a not so lovable one — over the saint, if the former will take the nation in the better direction.

Indeed, Martin Luther made the point several centuries ago when he famously favored a smart Turk over a stupid Christian as ruler. Few men in history have been as concerned about good theology and praxis. But he recognized that the civil magistrate is not principally concerned about theology and praxis. The official’s primary job is good governance.

There’s something more, however. Religious believers who focus on private beliefs are likely to be scammed. Consider the long succession of Republican politicians who have espoused family values — collecting a lot of votes in the process — while failing in their personal lives. The smartest among them remake themselves by admitting their sins and proclaiming their turn to God, collecting additional votes in the process.

It’s not that every profession of faith is false. But offering political rewards for personal testimonies encourages politicians to lie. Presumably Jim Bob Duggar believes President Obama is lying about being a Christian. Conversions are no easier to verify. As God told the prophet Samuel: “Man looks at the outward appearance, but the Lord looks at the heart.” (1 Sam. 16:7) Even such a public reprobate as Louisiana’s Edwin Edwards testified to Jesus’ divinity in one of his campaigns, a bizarre political manifestation in a state characterized by bizarre political manifestations.

The ludicrous practice continues today. For instance, Catholic convert Newt Gingrich, who seems to switch churches about as often as wives, said that he found “taking communion an enormously rewarding and deepening experience.” That’s nice — as one of my Catholic friends put it with some asperity, she was glad Catholicism “was working out for him.”

But presumably it is more important that he believe his faith to be true than to be comfortable. And however interesting his sentiment, how is it relevant to being president? Jimmy Carter taught Sunday school. That didn’t make him a good president. Ronald Reagan was divorced and never said what he thought of communion. That didn’t make him a bad president.

Gingrich also declared: “I pray before virtually every speech and virtually every major decision.” Assume that to be true. Again, so what? Jesus explained: “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven.” (Matt. 7:21) Even prayer is not likely to make a foolish, erratic, and egotistical believer with bad judgment a good president.

Nothing in Scripture says God will tell us the answers to all problems, whether or not we pray. One of our most common yet frustrating acts of faith is working in community with one another to solve common problems. That’s an important way Christians become salt and light. And it is how we exercise the wisdom given by God. (James 1:5)

The Bible offers no blueprint for government and says remarkably little about the role of the state. Conservative Christians often want to jail Americans for moral offenses and kill foreigners to make them good. Liberal Christians often want to steal money from Americans to demonstrate compassion and regulate Americans to make them good. All do so in the name of God, even though God never told Christians to use force to make anyone do much of anything. God’s instructions to people to behave a certain way toward each other and toward God do not mean, ipso facto, that they should imprison and/​or kill those who act otherwise.

And playing the religious card for one’s faith encourages others to play the card against. Joel McDurmon of American Vision criticized Rick Santorum’s Catholicism, explaining “imagine how complicated it gets when a man’s highest Spiritual allegiance is to the Vatican and not to the American people.” By the same logic, of course, Catholics might reciprocate concern over the lack of sound judgment of anyone outside the historic church. And non-believers could run away from those who claim to hear from God. Evangelicals likely will end up losers from playing the religion card.

Good Christians should be good citizens. But being a good citizen (or good government official) does not require being a good Christian.

Americans of all beliefs should focus on who would be the best president. One can imagine religiously-based policy disqualifications — if you fervently yet genuinely believe God wants government to arrest every sinner, I won’t vote for you, irrespective of your declared faith. However, the essential test should be ideology, not theology.

It is hard enough to assess who would implement the best policies. Imagine if voters also had to sort out who would find communion to be most rewarding.