A law is ultimately impose to you by the state, here US and Kansas state law. Sharia "law" would be at best a convention, an understanding between two willing parties. It's like the rules the Amish, Mormons, Ultra-Orthodox Jews and other communities voluntarily obey. Non of them can be used in court to justify braking a criminal (penal) law. All of them can be used to justify freedom of religion in relation to the state....unnecessary because American laws prevail on U.S. soil.
So the law passed in Kansas can range from being useless to infringing freedom of religion. An example of a law that can bring no good!
Furthermore you should check the study he put forward. It is exactly the same of crap the Daily Mail sells to actually pander to the populist, retrograde xenophobic strata of the British society. There is little Sharia in it.
Good,glad he's taking a stance against that throwback law.