Law in classical Muslim societies is similar to U.S. constitutional law in that there is a "separation of powers," Quraishi said.
"The parallels lie in the tools that are used to understand the meaning of the founding text," she said.
Islamic law can be divided into two areas, fiqh and siyasa law. Fiqh is law draw from the Qur'an and Sunnah as interpreted by legal scholars. Siyasa is law created by a temporal ruler for the purpose of maintaining public welfare and justice, Quraishi said.
Whereas fiqh involves laws pertaining to due process, property, family and rules of worship, siyasa involves laws that govern issues like marketplace regulation, taxes and security, Quraishi said.
"Everyone interprets [fiqh] in their own way," she said. "You have to treat other people's conclusions with respect."
Different interpretations of the Qur'an and Sunnah, Quraishi said, lead to many separate schools of fiqh. These different schools are similar to the various methodologies, including originalism and textualism, used in the U.S. law system.
"The Constitution doesn't tell you how to interpret [the law]," Quraishi said. "It just gives you rules."
Quraishi explained that the existence of both fiqh and siyasa allows both government and religious leaders to influence law. In the U.S. model, on the other hand, the government has a "monopoly on law," Quraishi said.
"In the U.S. system, what legal scholars write is commentary on the law, not the actual law," she said.
The only way to incorporate fiqh into the nation-state model used by countries like the United States would be to incorporate it into legislation, Quraishi said.
"However, that eliminates space to choose which type of fiqh you follow," she said.
In the classical Muslim societies, parties consult experts in the school of fiqh law to which they subscribe in order to resolve conflicts. Legislated fiqh eliminates this kind of flexibility of interpretation, Quraishi said.
The first amendment is in this way similar to fiqh, Quraishi said.
"They both serve the purpose of saying that the government should not control people's beliefs," she said.
Religious scholars have great social clout in Islamic law systems, but they do not want to justify rebellion, Quraishi said.
"Generally speaking, the government should not forbid something that is mandatory for Muslims to do, nor should it mandate what is prohibited," she said.
