What began in January with Mike Huckabee’s “Christian Leader” ads in Iowa and subterranean attacks on Mitt Romney’s Mormon faith has further degenerated into false rumors about Barack Obama’s faith and ugly stories about a “witch-hunting” pastor who once blessed Sarah Palin.

In the long history of religion in presidential campaigns, the 2008 race may well be remembered as the sleaziest and most disturbing example of misusing religion to win votes and demonize the opposition.

True, past campaigns featured smears against Thomas Jefferson as an “atheist and infidel,” attacks on William Howard Taft for being a Unitarian, and opposition to John Kennedy because of his Catholic faith (to cite a few examples).

But in Campaign 2008, the debate about who is and isn’t an authentic Christian has sunk to new lows. Consider the bizarre Internet-driven charges that Obama is the Antichrist, powerful venom aimed at influencing the millions of Americans who believe we live in the last days as described in the Book of Revelation.

Christian supporters of Obama charge that this calumny against their candidate is reinforced by a John McCain campaign ad featuring Obama as “the One,” using sound bites from Obama’s speeches and images familiar to readers of the Left Behind series, a popular fictionalized account of the end-time.

Although the McCain campaign claims the ad is only a joke, bloggers and commentators keep the story alive by continuing to debate every word and image.

In this theology-saturated climate, both Obama and McCain have felt compelled to emphasize their Christian bona fides in the race for the White House — as though the nation is electing a Christian in chief rather than a commander in chief.

McCain has sought to reassure evangelicals in the Republican base that he’s on their side. His selection of Sarah Palin is widely seen as having done just that. But now the blogosphere is ablaze with ridicule and disparagement of Palin as a “religious freak.”

Meanwhile, Obama’s campaign continues to be plagued by the lie that Obama is a Muslim. Apparently, the only time a religion other than Christianity gets mentioned in presidential politics is when it’s used as a slur.

According to a recent Pew Research Center poll, 12% of registered voters say Obama is a Muslim and another 25% of voters aren’t sure about his religion because they’ve heard “different things” about it. The lie about Obama’s faith has been so tenacious that Obama’s campaign has resorted to putting “committed Christian” on some of his literature.

Behind many of the rumors and innuendos is the subliminal message that only a “real Christian” is worthy to be president — a message that reinforces the “Christian nation” rhetoric of our culture wars.

Apparently, this false vision of America sells. According to the State of the First Amendment survey released by the First Amendment Center last week, an astounding 55% of the American people agree that the U.S. Constitution establishes a Christian nation.

Of course, the text of the Constitution does no such thing: It nowhere mentions God or Christ; it bars any religious test for public office; and it prohibits any law “respecting an establishment of religion.”

Under the First Amendment, Christianity has a legitimate role to play in political life (as do all religions). Religious motivation in public life and the involvement of religious groups in public policy are inevitable and laudatory byproducts of the constitutional guarantee of religious freedom.

Moreover, voters have every right to know how the religious views of candidates might shape policy decisions should they be elected.

But there is a critical difference between faith as motivation and faith as manipulation. Unlike the civil rights movement — where faith was a key motivation for many in the struggle for social justice — the current God strategy by candidates and their surrogates often uses religion as a weapon to destroy opponents in the name of winning elections.

Enough is enough.

It’s time for the candidates to set an example by dialing back the God talk. Speak out instead for what the Constitution actually requires: A president committed to upholding the First Amendment by keeping government out of religion while simultaneously ensuring that people of all faiths and none are treated with fairness and respect.

The Constitution, after all, starts off “We the People” — not “We the Christians.”

Charles C. Haynes is senior scholar at the First Amendment Center, 555 Pennsylvania Ave., N.W., Washington, D.C. 20001. Web: firstamendmentcenter.org. E-mail: chaynes@freedomforum.org.