First of all, Sharia law has 0% influence on American jurisprudence. Second, I doubt that anyone out there from the right have any understanding of Sharia law. They're filled with fear but have no idea of what they're afraid of. 

More likely than not, they are well steeped in those parts of the Bible that prescribe swift and certain death for 'certain people' and more than a few -- perhaps many of them -- are totally comfortable with a Christian God's vengeance.