This essay explains the slow but certain adaptation of Islamic law to a general audience:

David R. Vishanoff. “Islamic Law: A Long Work in Progress.” The Army Chaplaincy, Winter-Spring 2009, 65-68.

This article was originally accessible on the public websites of the Chief of Chaplains (http://www.chapnet.army.mil) and the U.S. Army Chaplain Center and School (USACHCS) (http://www.usachcs.army.mil/TACarchive/TAC/tac.htm), but as of 2017 these web sites no longer exist and The Army Chaplaincy no longer appears to be in publication or available online, so I am making a pdf of the article available here.