In recent years, the U.S. Supreme Court has been reluctant to respond favorably to constitutional challenges brought on the face of newly enacted state statutes. The facial challenge device has been used to challenge some of the most controversial legislation enacted in the states, including state-imposed voter identification requirements, new state primary election systems, and, recently in Arizona, immigration-related statutes. In this Article, I argue that the Court’s hesitancy to uphold facial challenges is specifically based on a reluctance to rely on speculation to defeat an untested state statute. I suggest that a direct focus on speculation in the constitutional analysis is useful, and I ultimately explore Arizona’s two controversial immigration-related statutes—and the facial challenges brought against them—to illustrate a role for speculation in facial challenges. Arizona’s employer sanctions statute was recently upheld by the Supreme Court on a facial challenge. The constitutionality of Arizona’s Senate Bill 1070 will likely be before the Court during its 2011–2012 term.