FORTUNATELY, no one is going to follow Newt Gingrich’s unconstitutional and un-American plan for an inquisition to “test every person here who is of a Muslim background” and deport the ones who “believe in Shariah.” Even Mr. Gingrich himself, a day after suggesting this policy in the wake of the terrorist attack in Nice, France, conceded that such a plan was impossible. But his proposal is a reminder of a persistent and inexcusable misunderstanding of what Shariah is, both in theory and in practice.
Put simply, for believing Muslims, Shariah is the ideal realization of divine justice — a higher law reflecting God’s will.
Muslims have a wide range of different beliefs about what Shariah requires in practice. And all agree that humans are imperfect interpreters of God’s will. But to ask a faithful Muslim if he or she “believes in” Shariah is essentially to ask if he or she accepts God’s word. In effect, Mr. Gingrich was proposing to deport all Muslims who consider themselves religious believers.
Start with a crucial distinction. Shariah doesn’t simply or exactly mean Islamic law. Properly speaking, Shariah refers to God’s blueprint for human life. It is divine and unchanging, reflecting God’s unity and perfection. It can be found in God’s revealed word in the Quran and in the divinely guided actions of the Prophet Muhammad.
In contrast, another Arabic word, “fiqh,” refers to the interpretation and application of Shariah in the real world. Fiqh is Islamic law as practiced by people. Because it’s a product of human reasoning used to understand God’s word, Islamic law is subject to debate and imperfection.
The distinction between Shariah and fiqh matters especially because Muslims, including religiously traditional Muslims, do not all agree on what Islamic law requires in practice. They’re disagreeing about what God wants, to be sure. But almost all faithful Muslims would say that they believe there is a single, truthful answer that lies in Shariah — we just cannot be absolutely sure as humans what that answer is.
In public discourse both in majority-Muslim countries and in the West, Shariah has come to take on other meanings. Advocates of political Islam — roughly, people who buy into the slogan “Islam is the answer” — sometimes use the term to describe a government that complies with the dictates of Islamic law.
Political Islamists — Islamists for short — recognize that the classical legal rules, derived from the Quran, the actions of the Prophet Muhammad, need to be supplemented by further legal and administrative regulations. When they seek to incorporate Shariah into their constitutions, they are usually asking for modern legislation informed by classical Islamic law, and also sometimes for a rule that no legislation may violate classical Islamic legal rules.
In Saudi Arabia, where there is no written constitution, classical Islamic legal principles function as a kind of unwritten, common-law constitution. But even Saudi Arabia has a body of administrative regulations that function a lot like legislation.
The ideologues of the Islamic State purport to follow Shariah exclusively. What that means in practice is that they justify their policies by reference to rulings that can be found in the vast corpus of classical Islamic legal writing. Often the positions they adopt have been repudiated by mainstream Islamic legal scholars for centuries. And the scholarship of the Islamic State legal thinkers is not technically excellent, measured by the standards of Islamic legal academies around the world. (The Taliban were less expert still, and sometimes called their rules Shariah-based even when they were in fact derived from Pashtun tribal custom.)
But it must be said that the Islamic State does try to ground all its practices in some Islamic basis. In this sense, it is laying claim to producing an Islamic utopia — one that its followers believe will come as close as possible to the divinely ordained Shariah.
ISLAMIC extremism and terrorism justified by Shariah have given fuel to American efforts to say that Shariah or Islam itself is the fundamental source of the problem. In 2010, Oklahoma overwhelmingly approved a state constitutional amendment prohibiting its courts “from considering or using Shariah law.”
The measure was legally unnecessary, since the establishment clause of the United States Constitution would already have prohibited civil courts from applying religious law. And in 2013, a federal district court rightly struck it down as an unconstitutional effort to single out Muslims and Islam.
Mr. Gingrich’s comments are the latest iteration in the effort to make Shariah into a target. His goal seems to be to disclaim condemnation of Muslims per se by saying that Muslims would not be dangerous as long as they rejected Shariah.
But that’s like saying Christians would be acceptable so long as they repudiated the doctrine of Christ’s divinity, or that Jews could be tolerated if they denied God’s revelation to Moses at Sinai. Shariah is that central to orthodox Islamic faith.
That doesn’t mean, however, that all Muslims accept the tenets of Islamic law as interpreted by the most traditional and extreme schools of thought. A vast majority of Muslims reject the use of Shariah to legitimate terrorism.
In his masterpiece, “What Is Islam?” published in 2015, the scholar Shahab Ahmed argued sharply against conflating Islam itself with Islamic law and orthodox doctrine. In his definition, Islam is a protean human phenomenon, rife with contradictions. At its core, Mr. Ahmed argued, Islam is a way of meaning-making through the text of the Quran, the world in which the Quranic text came to be, and the context of actual Muslims’ interpretation of both those things.
For most Muslims, Shariah is one part of that meaning-making effort. That’s why Muslims disagree about what Shariah entails — while believing that it is an important part of their tradition and faith.
is a professor of law at Harvard and a columnist for Bloomberg View.