Arizona's Governor Jan Brewer signed a bill into law on April 23, 2010 that makes it a state crime to be in Arizona illegally and requires state police to check the status of people they suspect to be illegal immigrants. The law also requires immigrants to carry their registration documents with them at all times. The law is controversial and has sparked considerable debate over its constitutionality, whether it authorizes police to engage in racial profiling, whether it will overwhelm local law enforcement and could possibly damage local economies. Arizona is the only state with this type of law. The law, which already is being challenged in court, could spark renewed interest in comprehensive immigration reform with the current administration.

While debates continue to rage, the law should serve as a reminder to foreign nationals that they are required by federal law, not just in Arizona, to carry with them and have in their personal possession at all times evidence of their U.S. immigration status. While having these documents in one's possession at all times is inconvenient, the law does require all foreign nationals to carry with them "any certificate of alien registration." Failure to comply with the law is punishable as a misdemeanor and carries a fine of up to $100 or imprisonment of up to 30 days, or both.