The court struck down several parts of Arizona's law but nonetheless left in place allowing police officers to check the immigration status of people in the state at specific times.

If police stop or arrest someone that they also suspect may be an illegal immigrant, they can under the law check that person's immigration status, the court ruled.

Arizona's police can't simply stop a person and ask for immigration papers simply because of their race, color or national origin.

However, a traffic stop, for instance, can be the trigger for an inquiry.

How complicated this gets may depend on the training of the police officer, his or her knowledge of work visas, and whether an H-1B worker in the state has an Arizona's driver's license.