While there may be some interpretations and facets of Sharia Law that are incompatible with democratic ideals and sensibilities, that doesn't mean that all interpretations and facets of Sharia Law are irreconcilable with American society. To reject religious laws as "foreign laws" is to unwittingly absolutize state sovereignty over our lives. There is a proper jurisdiction for religious laws among those who freely assent to membership in that religious community, just as their is a proper jurisdiction for the laws of parents within their own households (assuming those parental laws do not violate basic human rights and dignity). Sharia Law, within these understood boundaries, can function much like canon law does among Catholics, providing a system of laws independent of civil government for those in the Catholic community. All the better if such a system of laws can help take care of certain issues locally within those communities without needing the oversight of the state (again, provided that no is being beheaded for apostasy or dismembered for stealing).
Two articles that might be worth reading. The first deals with issue of "family sovereignty," arguing that the state is not an absolute lawgiver and must respect the proper jurisdiction of the family. The second makes some direct comparisons between the paranoia some Americans once felt toward Catholics and the similar paranoia currently being expressed toward Muslims.