As centuries go, the 20th will be one of the easiest to describe. It was the century of the West’s great and bloody civil war. It began with the assassination of the Archduke Ferdinand. It ended with the fall of the Berlin Wall. It was a century when the notion of individual rights spread around the world. It was a century when the rights of individuals were never more egregiously attacked. It was the century of great war between those who worshipped the state and those who championed the individual in the face of state power. The United States was drawn into the first chapter of the great civil war in 1917. We were drawn into the second chapter in 1941. We led the final and decisive battle in the last half of the last century.

The 21st century has begun with our being drawn into Islam’s civil war. It is a war between those who idolize a political and totalitarian Islam and those who champion a traditional Islam, an Islam of many varied and even conflicting voices. Like the West’s civil war, Islam’s civil war is being waged ideologically and diplomatically as much as it is militarily.

Hitler’s greatest triumphs were diplomatic, when he convinced the leaders of the democracies that if they would only satisfy some deep-seated territorial needs of Germany, all would be well. He gained sympathy because democratic leaders felt some guilt in having imposed the onerous Versailles treaty on Germany. He gained power and sympathy in Germany on the basis of the same harms. Most of all, he convinced many in Germany that they were victims of a great grasping conspiracy of international Jewry. He attacked religion and freedom. And he destroyed millions of lives.

The Soviet Union had much more ideological success when it took on the mantle of the expansionist totalitarian state. It too set up a great devil: international capitalism. It gained many sympathizers among the free world’s intelligentsia. It played upon the poverty of the third world. It set up fifth columns around the world. It developed a network of client states and sympathetic political parties. It attacked religion and freedom. And it destroyed millions of lives.

Hitler and Stalin had sympathizers and even allies. They were the anti-Semites, or the fellow travelers, intellectuals who championed eugenics, or intellectuals who championed Marx. Bin Laden has sympathizers and allies within the Muslim world. Some are rigid fundamentalists. Some are intellectuals. Some are merely anti-American. Some are repelled by secularism.

The free world won the civil war in the West when it realized that it was engaged in a battle against evil, against the lust for power, against the false god of politics. It took a while. The West had to struggle against the moral relativism that obscured the real aims of Communism. Only when the free world’s leaders unabashedly saw that it was a moral cause that they defended, only when they called upon the religious traditions of the West that championed the inherent dignity and respect of each individual, only when we affirmed the inestimable good of freedom, did we have the will to stay the course and overcome the threat. It was Truman, Reagan, Thatcher, and it was Pope John Paul II who called the evil for what it was and shook down its rotten edifice.

Bin Laden’s extremism has not yet consolidated its power, the way Nazism did in Germany and Bolshevism in Russia, unless of course, you call Afghanistan a consolidation. But it has the same objectives, and uses the same methods. It seeks to dominate Islam with a political ideology free of even the constraints of the classical law of Islam. It uses methods of organized terror parallel to Naziism and Bolshevism. It sets up cells as the Communists did. It makes effective use of propaganda. It justifies itself by calling upon political symbols, not the Rhineland or the Sudetenland, but Saudi Arabia, Palestine, Andalusia. It lists political wrongs: the crusades and the post World War I settlement, just as Hitler did. And it creates the great Satan: America and International Jewry. If it succeeds, it will do to Islam what Hitler did to Germany and nations it overran, and what Stalin did to Russia and the nations it overran.

Like Naziism and Communism, Islamic extremism has its own powerful ideological apologists. Nazism claimed that Germany was rotten because of the influence of the Jews. Bolshevism asserted that Russia was rotten because of the mind-set of the petit bourgeoisie. Extremist Islamist ideologues assert that Islam is now rotten because of Western inroads. The Islamic world itself is in a state of ignorance, they claim, just as was pre-Islamic Arabia, and the war is against unbelievers even if they try to call themselves Muslims.

In the West, the free world that won the civil war against terror and tyranny now examines what it is it fought for, what it is to become. The free world set its face against evil, but that does not insulate us against institutional imperfections, against the sins of flawed human nature. Are we to be secular, or religiously inspired? Are we to be a community, or riven by divisions? Are we to be acquisitive and materialistic, or, as shown by this country after the world trade center attacks, generous, faith filled, and self-sacrificing?

The same kind of self-examination in Islam now comes in the train of its own civil war against evil. And the primary question will be, as it always has been for Islamic civilization, what will be the place of law in the religion? Will it be an adjunct to spirituality and righteousness, or will it be a set of rules that constrain, that are valued for its own sake, not for what it permits the expansive spiritual soul?

Let us first sketch some of the early trends in Islam, and note how law became such a dominant voice in Islam.

Barely a quarter century after the death of the Prophet, Islam was rent by a civil war between the adherents of the assassinated third Caliph, Uthman, and the partisans of Ali, the fourth Caliph. The war eventually led to the division between Sunni and Shi’a Islam. But while the question of the political leadership of Islam was disputed, a philosophical and theological debate began that has never really ended.

One group, the Murji’tes, became the advocates of toleration and equality within Islam. They counseled peace to the warring parties, recognized non-Arab Muslims as equal to Arabs, accepted even a sinning Muslim as still a member of the faith, and emphasized faith over works as the means to salvation. They were not enamored of the law. The Murji’tes reflected Islam as a religion of toleration, openness, faithfulness, and peace.

A second party, the Mu’tazilites, championed the role of reason within Islam. They made use of works of pagan philosophers that had come into the expanded Islamic empire. Reason, the Mu’tazilites taught, could ascertain the truth even without the aid of revelation. Good and evil could be known by all men. But because of the weakness of the human will, revelation was necessary to confirm to man what was truly good and to provide men with rules of behavior that unaided reason could not apprehend. Nonetheless, reason directs the understanding of revelation. God would not command of man that which would be absurd or unreasonable.

Eventually, the Mu’tazilites lost the struggle with the Legalists to become the dominant ideology of the Islamic empire. But as a party, they were not extinguished until the Mongols invaded Islam and destroyed Baghdad and its great centers of learning. In a deep intellectual sense, Islam has never yet recovered from the Mongol invasion. Nonetheless, many of the great Islamic philosophers like al-Farabi, Avicenna and Averroes, though not of the Mu’tazilite party, championed reason. Many modern-day Islamic reformers and thinkers are also, in their own way, heirs to the Mu’tazilite tradition.

A third group, the Kharijites, was the enemy of all. The Kharijites held that any person who strayed from the perfect practice of Islam was ipso facto an apostate subject to being killed with impunity. Any leader who did not hold true to the principles of Islam was likewise illegitimate and should be overthrown and killed. Ali himself eventually died at their hands. The Kharijites were never fully unified in command or tactics. But true to their beliefs, they committed frightful massacres on Muslims whom they believed no longer practiced the faith.

Their theology followed their politics. They absolutely rejected the doctrine of salvation by faith and embraced the belief of salvation by works. Practice and only practice determined who was a true Muslim. It took two centuries of war before the Kharijites were effectively suppressed and rejected by all the other Islamic traditions. Today, radicals who attack civilians, who define who it is they regard as a true Muslim on pain of suppression and death, replicate that ancient sect.

The Legalists, of course, bested their rivals to become the dominant voice in Islam. They began as executive bureaucrats of the empire, functionaries that had to enforce imperial decrees. They grouped into legal schools and were challenged and later melded with a pietistic movement that sought to impose Qur’anic norms throughout the empire. Over the centuries, they developed the system of law, the Shari’a, that was in many ways more than 500 years ahead of the English common law. Their rules on commercial law, partnerships, agency, and succession were some of the most sophisticated of any legal system. Where the rules of the Shari’a got in the way of state governance, such as in the criminal law, the authorities simply removed the qadi from jurisdiction and set up their own state courts. That is why the criminal portions of the Shari’a remained undeveloped. Today, when modern fundamentalists seek to reimpose the Shari’a, even its criminal elements, they try to put in place part of the law that was incomplete even in its own time.

But the Legalists rigidified the law and radicalized it in certain areas, such as the law of apostasy and the obligation to engage in a military jihad. After the Mongol invasion and the rise of the Ottomans and, in South Asia, the Mughal Empire, the Legalists became the dominant intellectual voice of Islam, though it was not a creative intellectualism. They preserved their tradition through the self-perpetuating class of religious scholars, the Ulema. They became the court party of the Ottomans and influenced the empire greatly.

Their dry legalisms, their theory that one attained heaven only by following all the details of the law, offended Muslims of a more spiritual bent. There arose in opposition to the legalists the Sufi movement. The Sufis were the mystical element in Islam, that part that produced some of the greatest writings, poetry, and spiritual mentors of the religion. As the legalists became the dominant intellectual voice of Islam during the Ottoman empire, the Sufis became its dominant spiritual voice.

Until 1685, Islam had continued to expand (except for the loss of Spain). For centuries, Islam experienced a worldly triumphalism that deeply affected its consciousness. On September 11, 1685, the Ottomans were finally turned back from the gates of Vienna in a decisive defeat. There then began three centuries of steady erosion of Islamic power culminating in the 20th century in the virtual occupation of all of Islam by Western powers. In the face of that rolling retreat, in the face of Western artistic, technological, political, and intellectual prowess, Muslim intellectuals sought to understand the reasons for the defeat and to devise methods of an Islamic resurgence. It was among these competing visions of a resurgent Islam that the great civil war within Islam began, the civil war we are now drawn into.

There were two main groups of disputants in the debate over the resurgence of Islam, each containing multiple and conflicting variations. One group of fundamentalists, the Wahhabis, asserted the most extreme and puritanical version of the Shari’a. Beginning in the late 18th century, they came to dominate Saudi Arabia, and their proseltyzation of their views has increased anti-Western thought and provided a fertile ground for political radicalism. Another group of traditional fundamentalists, those who wished the state to reimpose the Shari’a transmogrified in to the politicized terrorist extremists we have seen throughout the Islamic world. Finally, a group of reformers arose, ranging from the secularists that gained power into Turkey to men like Muhammed Iqbal, the spiritual founder of Pakistan. Iqbal, fully conversant with Western philosophy, called for a reconstruction of religious thought in Islam. He thought the Shari’a of the tenth century needed to be overcome and the law redeveloped from its roots. And he believed that elected legislatures, not the Ulema, had the authority to propound such genuinely new laws. He stated, "The only alternative open to us, then, is to tear off from Islam the hard crust which has immobilized an essentially dynamic outlook on life, and to rediscover the original verities of freedom, equality, and solidarity with a view to rebuild our moral, social, and political ideals out of their original simplicity and universality." Yet today, despite Iqbal, Pakistan remains riven by tribalism, privilege, and ignorance.

It is a difficult civil war we have been driven into. But we can know, at least, that once again, we are on the right side.

David Forte is a Professor of Law at Cleveland-Marshall College of Law in Cleveland, Ohio and the author of Islamic Studies: Classical and Contemporary Applications. He is an Adjunct Fellow of the Ashbrook Center.