President Dwight Eisenhower signed the bill making "In God We Trust" the nation's official motto, but his approach to religion was not excessive in its rigor. "Our form of government has no sense unless it is founded in a deeply felt religious belief," he once declared, "and I don't care what it is."
He might have been taken aback at the spectacle presented by fellow Republican Ted Cruz Monday in Lynchburg, Va. The Texas senator sounded less like he was running for president of the United States than for president of the Southern Baptist Convention.
Part of the message was the setting -- a stage at Liberty University, founded by televangelist Jerry Falwell, which Cruz saluted as "the largest Christian university in the world."
He holds degrees from Princeton and Harvard, but he was right at home there. He noted that his wife's parents were missionaries in Africa. He said America's urgently needed reclamation would come from "people of faith."
He testified that when his father was contemplating divorce, "God transformed his heart." He informed his audience that "were it not for the transformative love of Jesus Christ," he "would have been raised by a single mom without my father in the household."
Invocations of the Almighty have long been a normal and harmless part of American political rhetoric. Even Barack Obama, whom many people continue to believe is a Muslim rather than a Christian, ends his speeches, "God bless you, and God bless the United States of America."
But Cruz takes this custom to a novel extreme. He was not paying the normal tribute to general and widely held Christian beliefs. He was informing a narrow slice of Protestants, "I'm one of you." Most religious expressions by politicians are inclusionary. His was the opposite.
Politically this sounds like a losing long-term strategy, since white evangelicals (the chief target of his appeal) make up a small, shrinking group. Today, they are only 18 percent of the population -- just slightly more than the percentage with no religious affiliation. Cruz's message will alienate at least as many people as it will attract.
It puts him in a geographic box as well as a sectarian one, since white evangelicals disproportionately live in the South. It hinders him with younger voters, who are the least likely to be born-again Christians.
But in the short run, or the Republican primaries, his born-again appeals may help him compete against candidates like Mike Huckabee, an ordained Southern Baptist minister, Rick Santorum, a religious culture warrior, and Scott Walker, son of a Baptist minister. One of them is bound to use this campaign slogan: "Jesus loves you, but I'm his favorite."
It's hard to believe that white Southern evangelicals once took a very different view of politics. In 1960, when Democratic candidate John Kennedy needed to address concerns about his Catholic faith -- something no president had shared -- he spoke to Protestant pastors in Houston.
"I believe in an America where the separation of church and state is absolute," he proclaimed. "I believe in a president whose religious views are his own private affair, neither imposed by him upon the nation, or imposed by the nation on him as a condition to holding that office."
When he was done, his audience applauded. If a politician were to say the same thing to modern evangelicals, they would be more likely to sit in stony silence.
Cruz is unabashed in implying that his religious views are an excellent reason to vote for him. He also thinks they are, and should be, inseparable from his views on policy. He won't get much argument in GOP debates.
But JFK was on to something that ostentatiously Christian politicians ignore. In a pluralist society that abstains from state aid to churches, candidates may be guided by their faith, but they have a duty to advocate their political views in terms that transcend religion.
"God wants it" is not a legitimate rationale for any government policy. Cruz, however, is the culmination of years of effort by Republicans to present themselves as the official sponsor of Christianity.
They have come a long way from Sen. Barry Goldwater, the famously conservative 1964 presidential nominee. When Ronald Reagan appointed Sandra Day O'Connor to the Supreme Court, an unhappy Jerry Falwell said that "every good Christian should be concerned." Goldwater had a different suggestion: "Every good Christian ought to kick Falwell right in the ass."