Pope Benedict XVI did the right thing, twice. In his talk to scholars in Germany, he correctly put Islam in historical perspective, describing how Islam was perceived as "evil and inhuman" by a 14th-century Christian emperor desperate for the help of other Christians to defend his country against Islamic conquest. (His fellow Christians didn't help.)

He was correct this week as well, to say he was "deeply sorry for the reactions in some countries to a few passages." He clearly wanted to put a lid on the violence without contradicting his earlier remarks. Benedict, reasonably enough, called for reflection to seek the "true sense of his words" about how violence is the wrong approach to faith. Who among us could disagree with that? (A lot of Muslims, to be sure.)

Words, unlike knives and suicide bombs, don't kill, and when facts buried in arcane scholarship come to light they can nudge thoughtful men and women toward the genuine interfaith discussion Pope Benedict sought when he asked for "frank and sincere dialogue with mutual respect." A Muslim leader who asked for such an intellectual debate would not be faulted for calling attention to the evil of the Crusades, which also sought to make converts through the sword or the burning of heretics.

The modern world today is engaged in an unprecedented attempt to understand Islam, confronting its two faces -- one ferociously bent on destroying everything Western and the other professing appreciation for the Western values underlying peaceful secular and pluralistic societies. Optimists see the smiley face of Islam, and applaud. Pessimists see a mask covering the motives of evil men who are determined to eradicate Western civilization as we know it, and despair.

The rioters who killed an Italian nun in Mogadishu and burned Christian churches in Palestine support the pessimistic view. Those who retreat from denouncing this violence for fear of offending violent Islamists are giving in to blackmail. The Turks used the pope's remarks to focus criticism of him because he opposes admitting Turkey into the European Union. The violent reactions substantiate his belief that Turkish admission would expand Islamic fanaticism in Europe.

Pope Benedict has been compared to Pope John II, who was a major force against communist tyranny, and suffers in the comparison. But fighting communism was easier because communism did not hide behind appeals to religious tolerance. Communism was openly and forcefully intolerant of religion. No one questioned that. Oriana Fallaci, who died last week, was an effective Cassandra in identifying threats posed by radical Islamic states. In her book "The Rage and the Pride," she asked: "Aren't Islamic tyrannies as unacceptable and inadmissible as the fascist and communist ones?" That's the question, harsh but real, that we must deal with if civilization survives the radical Islamic threat.

A real debate over religious intolerance must include a discussion of modern Islam's violent streak. Cardinal Walter Kasper, the Catholic Church's ecumenical point man, describes some of the obstacles. "There is no such thing as one Islam," he told der Spiegel magazine. "The Koran is ambiguous and Islam is not a monolithic entity. The distinction between radical Islam and moderate Muslims is important, as are the differences between Sunnis and Shiites, and between militant and mystical Islam. Islam in the Arab world coexists with Indonesian, Pakistani and Turkish Islam."

The distinctions are important, and Muslims rarely speak with a unified voice, but there is little dissent from the jeremiads against America and Israel. Moderate Muslims, whatever their numbers, refuse to take over the debate against the violence enacted by their brothers, either because they're intimidated or sympathetic (or both). The fractures between radical and moderate Muslims are moot when Islamists busy their giddy minds with hatred for those who don't agree with them. Nevertheless, distinctions are crucial to the debate the pope is trying to get started. We have to hope the pessimists are wrong, that it's not a mission impossible.

Benedict has a supple and scholarly mind that is immune to the simplistic spiel of the spinmeisters. Like most scholars, he understands that great ideas are nearly always profoundly complex and subject to misreading. The violent reaction to his tough, provocative speech to the Catholic seminarians merely proved the point that he was trying to make:

"Whoever would lead someone to faith needs the ability to speak well and to reason properly, without violence and threats." Who can get that message? Can it be heard over the din of nihilism? Maybe, maybe not. But it's up to reasonable Muslims to see that the message gets out.