Republican presidential candidate Rick Santorum has said sharia law is an "existential threat" to America

Oklahoma, Tennessee and Louisiana each passed laws or referendums to ban state judges from considering sharia and other foreign laws last year, and more than 20 other states have debated similar legislation. Newt Gingrich has called for a federal law to ban sharia, while his fellow Republican presidential candidate Rick Santorum has said sharia law is an "existential threat" to America