Florida legislators are under attack from a terrorist front group for considering a bill aimed at banning the application of Sharia law—the authoritarian doctrine that inspires Islamists and their jihadism—from courtrooms throughout the state. Though it really targets Sharia, the measure seeks to prohibit the application of any foreign law, code or system in legal cases, especially in family court. It was introduced after a state appeals court allowed a county judge in central Florida to consider “ecclesiastical Islamic law” to decide a civil case involving a mosque. As a Florida state House committee considers the bill this week,...