Arizona passed the toughest immigration law in the country on Tuesday. The new measure, according to the Los Angeles Times, makes it a misdemeanor to lack immigration paperwork and compels police officers to determine immigration status if they form a "reasonable suspicion" that a person is in the U.S. illegally. Currently, police officers can only investigate immigration status if the person is a criminal suspect. Republican Gov. Jan Brewer is expected to sign the bill, although not everyone's on board. Police are split on the matter, with unions backing the measure but the state police chief's association opposing it on the grounds that it could damage the relationship between police and immigrants who are potential witnesses. The ACLU has also said it plans to sue to block the bill should Brewer sign it.