Here was Mitt Romney’s problem, one of the toughest in American politics: He had spent most of his campaign for the 2008 Republican presidential nomination in search of the faith vote while fleeing from talk of his own faith.

Now, Romney, a member of one of America’s leading political and Mormon families, has delivered a speech that no historian of the current presidential election, or of contemporary politics and culture, will be able to ignore.

In an address at the George H.W. Bush Presidential Library in College Station, Texas, that may turn out to be the most enduring campaign speech of the past four decades, the former Massachusetts governor told Americans that he did not “define my candidacy by my religion” and promised that “no authority of my church … will ever exert influence on presidential decisions.”

Romney’s speech was not delivered in a vacuum, politically or historically. Politically it came at a time when his campaign – so slick, so well-funded, so successful in choosing the times and places for its initiatives – was jolted by the rise of an unscripted, poorly funded candidate with deep roots in the Republican Party’s evangelical base.

This new force is former Gov. Mike Huckabee of Arkansas, who burst to the front of the Republican pack in Iowa last week – a candidate who, it should not go unnoticed, threatened to beat the shrewd Mitt Romney MBA at his own game, which is to get more than a dollar’s value for a dollar in spending. Indeed, Huckabee attracts twice as much evangelical support in Iowa as Romney does, according to a Pew Poll released last week – an important advantage given that evangelicals account for about two-fifths of likely caucus-goers.

Historically, Romney’s remarks came at a time when the rhetoric of the religious sphere is intersecting with the rhetoric of the political sphere to a greater degree than it has in generations; it is not too much to say that in recent decades American politicians have added an invocation to their vocation.

The speech came with a ready-made historical backdrop: the address that Sen. John F. Kennedy of Massachusetts delivered to the Greater Houston Ministerial Association in the 1960 campaign. In those remarks, the second Catholic presidential nominee in American history confronted head-on the skepticism (or worse) that some Americans had of people of his faith.

But like so much in our past, the folklore surrounding the Kennedy speech trumps the actual text. In our minds, Kennedy confronted the ministers by saying that if he lost his chance at the White House on the day he was baptized, then the nation was the poorer for that. In the American memory, this was perhaps the greatest statement ever delivered in support of diversity (a term not then in use, and a term that would have defied understanding at the end of the Eisenhower period).

Now we understand far more clearly that the separation of church and state is not at all the same as the separation of religion from American politics. “JFK’s speech is very dated,” says Wilfred M. McClary, the noted expert in American intellectual and cultural history who teaches at the University of Tennessee at Chattanooga. “He played the strict separationist card. We’ve come a great distance in saying that religion does have a place.”

Romney made that point. He argued for separation of church and state, not separation of church from state. But he made it clear that there was room in America for more than one church, and that all of them don’t even have to be churches.

“Each religion has its own unique doctrines and history,” he said. “These are not bases for criticism but rather a test of our tolerance. Religious tolerance would be a shallow principle indeed if it were reserved only for faiths with which we agree.”

When Kennedy gave his speech, there prevailed in the United States the notion that Protestants, Catholics and Jews, for all their differences, and for all the very real tensions among them, and for all the fears they sowed about each other, nonetheless were mainstream and familiar figures – though I think it is possible to argue that there are elements in all religions that are odd, even fantastic. That may be why religions are called faiths.

Though the Book of Mormon is a book about Jesus, Romney had a bigger burden than Kennedy bore, speaking about a faith that, while native to American soil and one of the fastest-growing religions in the world, is newer than other religions and less familiar in the American pageant. In a nation where, as Stephen Prothero, a Boston University religious studies professor, puts it, “Americans are very religious but know nothing about religion,” one of the things Americans think they know is that Mormons are different.

Evangelicals know one thing more: They compete with Mormon missionaries around the world. A Wall Street Journal/NBC News Poll taken last month showed that Americans were far more ready to send to the White House a woman (69 percent said it would be acceptable) or an African American (63 percent) than a Mormon (38 percent).

Romney addressed matters of his own faith Thursday in providing America with its first real Mormon moment. “I believe Jesus Christ is the son of God and the savior of mankind.” But he also said that if he takes the oath of office on Jan. 20, 2009, “that oath becomes my highest promise to God.”

This is a country where religious forces have never been far in the background; the faith factor has often influenced our politics. And it is legitimate to argue that abolitionism, early feminism, prohibitionism and the civil-rights movement were fueled in large measure by clerics and were advocated in religious, even biblical, rhetoric. Now, this force that has been so influential in American reform is asserting itself in American elections.

“No candidate should become the spokesman for his faith,” Romney said, “for if he becomes president he will need the prayers of the people of all faiths.” To which I add: Amen.