An estimated 11 million people live in the United States -- illegally. Two years ago, Arizona passed the broadest and strictest anti-illegal immigration measure in recent U.S. history, inspiring other states to follow suit. Tomorrow, the Supreme Court will hear arguments about whether that law is constitutional. It allows police officers to ask about the immigration status of anyone they stop. Critics say the law will lead to racial profiling. Supporters say it makes up for weak enforcement efforts by the federal government. A ruling is expected this summer, in the middle of the presidential campaign. Guest host Susan Page and guests discuss how far states can go to enforce immigration laws.