Officers of the law have now begun to enforce the “papers, please” provision of Arizona’s Senate Bill 1070, Reuters has reported. This means they can demand proof of legal residency from anyone they stop and suspect of being in the country illegally. The law made failure to carry this paperwork — which federal law requires aliens to carry — a state criminal misdemeanor. A court order had temporarily forbidden enforcement of this provision, but the injunction was lifted yesterday (Wednesday, Sept. 19, 2012).

Supporters and opponents of the law both are likely to observe very closely how the law is enforced. Although the U.S. Supreme Court upheld this particular provision of the law (while striking down most others), it sent strong signals that enforcement of the law could be subject to judicial review. Arizona Gov. Jan Brewer has promised that there will be no racial profiling, and the law expressly forbids it, but opponents such as the American Civil Liberties Union and the National Immigration Law Center are skeptical. The ACLU has set up a hotline where people can report what they feel are improper detentions. Senate Bill 1070 may not have seen its last day in court.