Romney has argued that a key step to reducing illegal immigration would be to reduce the job opportunities available for undocumented immigrants. He has said that requiring employers to confirm each worker's immigration status using an E-Verify-type database, such as in Arizona, and punishing employers who hire workers lacking proper documentation, would lead employers to stop hiring undocumented immigrants, with the result that fewer immigrants would choose to come to the U.S. illegally, and many of those who are already in the U.S. would "self-deport."