There's at least one reason to give thanks in the wake of Hurricane Katrina: We haven't heard televangelist Pat Robertson attribute the disaster to God's judgment of the paganism of New Orleans -- at least not yet.

There's something deeply troubling when a very visible Christian leader can be counted on to mouth an offensive or bizarre political opinion, as he did with his recent riff about assassinating the Venezuelan president. Media pundits, in a miasma of indignation, predictably bludgeoned evangelicals and their political allies with the latest absurdity. Rather than losing faith, many of Robertson's supporters undoubtedly signed bigger checks for his ministry.

The problem is not that this script is getting old. The real problem is that we've entered a 9/11 era of religious fanaticism, making the role of religion in public life deeply suspect. At exactly the moment when the need for effective Christian leadership could not be greater, it remains difficult to find.

Nearly all of the major Christian traditions in the United States, in fact, are on the defensive as never before. The Catholic Church still struggles to overcome its crisis of sexually abusive priests. Liberal Protestant churches, mimicking the secular cant of political activists, have bled themselves dry in membership and prestige. Though growing in numbers and political influence, evangelicals are among the most feared demographic group in the country, according to a recent Pew Forum poll.

Here's one reason: An evangelical figure with Robertson's clout talks like a hit man from the Sopranos -- and what do his religious brethren do about it? Not much.

True, a number of Christian leaders immediately criticized Robertson for his "extreme, fanatical" remarks. But just as many evaded the issue. Most kept quiet. Some claimed he wasn't speaking as a Christian leader (which would be news to his 700 Club audience). Others complained that his comments endangered the work of missionaries in Venezuela.

This misses the point. Robertson has a 20-year record of reckless statements and duplicitous behavior, all under the sanctified umbrella of Christian ministry. He once predicted divine judgment for Orlando, in the form of a hurricane, if Disney World allowed gay-pride events on its premises. While trying to negotiate a deal to get his CBN network into China, he downplayed the communist state's one-child policy (accomplished by forced sterilizations and abortions). Mindful of his financial investments in Africa, he defended Liberian thug Charles Taylor as a man of God -- up until the moment Taylor was indicted for war crimes and forced into exile.

In the age of Islamic terror, an American minister who pontificates about international politics has a civic -- and moral -- obligation to think before he opens his mouth. Robertson called for a political assassination, news that rippled into the Muslim world. Then, with classic Bill Clinton panache, he lied about it -- and then apologized. The question with Pat Robertson is not whether his fatuousness will reassert itself, but when.

Before it does, evangelical leaders would be wise to marginalize Robertson and his media empire -- publicly and decisively. They should editorialize against his excesses, refuse to appear on his television program, and deny him advertising space in their magazines. Board members should threaten to resign unless he steps down from his public platform. Religious leaders rightly worry about airing their dirty laundry. But Robertson has made himself a public figure -- and a massive public relations problem for the church. Until more evangelicals make a visible break with him, they'll be vulnerable to the crass caricatures that dominate media coverage of conservative religion in America.

In an intensely partisan era, with so much at stake politically, it's tempting to simply ignore the failings of one's allies in the culture wars. Yet without integrity, cultural influence is impossible. As the apostle Peter once warned, not so delicately, judgment begins with the family of God.

Mr. Loconte is a research fellow in religion at the Heritage Foundation and editor of "The End of Illusions: Religious Leaders Confront Hitler's Gathering Storm" (Rowman & Littlefield). He served as a member of the Congressional Task Force on the United Nations.