He has spearheaded major lawsuits across the country involving constitutional issues of particular concern to the American Muslim community, including the successful landmark challenge to Oklahoma’s State Question 755, a voter-approved referendum that would have barred reference to Islamic religious traditions in Oklahoma's courts. Gadeir has also litigated on behalf of American Muslims surveilled by warrantless GPS tracking devices, placed on the federal government’s terrorist watch lists, and prevented from building schools and mosques by discriminatory zoning laws.