This would be alarming if it were true. I read an article written by a person who attended the speech where Koh was supposed to have endorsed sharia law and he never said anything like that. It looks like this is an intentional lie made up by Republican opponets of Obama.

This would run counter to Obama's encouraging statement yesterday that America is not Christian, Jewish or any other sort of religious nation. Even though there probably some followers of Islam who would try to impose sharia here and in other western nations I doubt they will ever succeed in doing so even in any local governments. The Christian variety of fundamentalists would like to impose a theocracy and they have not gotten anywhere even though Christianity is the majority religion in the U.S. Of course in either case we should never let our guard down.