Like the fall of the Berlin Wall in 1989, the destruction of the World Trade Center last Tuesday is a turning point in history. But whilst the former was a joyful exclamation mark at the end of the Cold War, the latter is a blood-dipped capital letter at the start of a new chapter. The conflict between capitalism and communism has been replaced by another ideological battle, a fight between those who embrace the Enlightenment and those who reject it.

The World Trade Center symbolized technology, prosperity and the individualistic creed. It was located at the cultural and financial heart of a tolerant, democratic, dynamic nation where people speak, pray and dress as they please. It was, in other words, a distillation in metal and glass of the post-Enlightenment Western belief that reason is the key to human progress. The Islamist terrorist organizations that seek to bring down the United States propose, as an alternative model, an Islamic dictatorship fashioned on utopian visions of 7th-century Mohammedan rule. In nations under Islamist regimes, such as Sudan, Iran and Taliban-ruled Afghanistan, there is no separation between church and state; the legal system is controlled by religious zealots; criticism of the state religion is punishable by death; technology and science are frowned on except where necessary to secure state power; anti-Semitism is preached as a state religion and women are treated as property. The comparison with the Cold War could not be more stark. In that battle, East and West argued with one another about the true path of modernity, which each sought. Islamists, on the other hand, openly embrace a mode of life and government that is centuries out of date.

The West's message to the rest of the world must be simple: Choose a side. Either you are for civilization or you are against it. By providing refuge to Islamist terrorists, the Taliban regime in Afghanistan is facilitating mass murder. But its decision to do so is at least consistent with its crabbed ideology. In other corners of the Muslim world, however, such as Iran, Syria and Libya, governments give lip service to peace and progress while countenancing groups that support, finance, train and execute terrorist attacks. In Pakistan, militant religious academies openly train aspiring terrorists. And in the Palestinian Authority, terrorist groups such as Hamas and Islamic Jihad, which wish to annihilate Israel, are openly encouraged. Following the failure of last year's peace talks at Camp David, Yasser Arafat freed dozens of terrorists in a failed bid to strengthen his bargaining position.

Sensibly, U.S. President George W. Bush has eschewed the option of a massive, instant retaliation for last week's terror attack. That would have ministered to Americans' outrage and understandable longing for vengeance, but would have done little to advance the country's long-term interest of drawing nations into a U.S.-led campaign to isolate, discredit and attack nations that encourage terrorism. It goes without saying that Israel, Canada, NATO, the European Union and the rest of the world's democracies will join the United States. Russia, China, Turkey and the former Soviet republics in Central Asia must also be brought in as partners.

The greater challenge will be getting commitments from Muslim nations that are besieged or influenced by Islamist constituencies -- such as Pakistan, Egypt, Jordan, Saudi Arabia, Yemen and Algeria. These nations are close to the fissure between the pre- and post-Enlightenment worlds. While none is overly anxious to accommodate the United States as a matter of policy, their leaders should realize that taking the side of civilization is a matter of self-interest. Witness the misery, chaos and poverty on display in states that have adopted Islamist policies: Afghanistan is an economic ruin that, ironically, relies on aid from the United States and other Western nations to avoid mass starvation. Sudan is an impoverished hellhole enmeshed in an unending race war. In Iran, per capita income has fallen by 75% since the Shah was deposed in 1979. The fence-sitters have another reason for joining the United States: Islamist terrorists are targeting them, too. One foiled plot recently linked to Osama bin Laden involved blowing up the Radisson Hotel in Jordan. Bin Laden lives in a cave and appears to think other Muslims should, too.

By situating the ideological struggle between the West and Islamist terrorists in its proper context, we can do away with the facile theory that Tuesday's attack was brought about by U.S. "imperialism" or its support for Israel. What fills Islamists with rage is not the fact that the United States pushes its culture on the Muslim world but that so many people in the Muslim world are eager to receive it. Across the Middle East, visa lines are long at U.S. embassies. Palestinian children celebrate terrorist attacks wearing Nikes. Titanic was so popular in Afghanistan that Taliban leaders had to ban Leonardo DiCaprio haircuts. In Peshawar, Internet cafés are used mostly for surfing pornography. As for Israel, Islamists despise and attack it not out of compassion for Palestinians, who are treated like dirt in neighboring Arab countries, but as a rich and prosperous surrogate for the post-Enlightenment world. Israel is the sole modern country in a sea of backwardness.

On Tuesday, the terrorists cut out the middleman, with the result that the United States has been stirred to battle. We do not doubt that it will be a long and frustrating contest. But we have every hope and belief that the side of enlightened civilization will prevail.