In New York City, home to the nation's largest Italian American population and led by Italian American Mayor Fiorello LaGuardia, Italian immigrants were photographed, fingerprinted and registered with the Department of Justice and the FBI. The government told Italian resident aliens to stay off the streets after dark. Daytime travel was restricted. To walk the streets or subway to work, Italian resident aliens in New York City carried bright pink enemy alien passbooks, with photo ID and fingerprint.

Failure to produce the passbook upon demand of a government agent often resulted in arrest. Spoken Italian in public places was officially discouraged by the Federal government.

In Washington, D.C. the attorney general decreed that an Italian resident alien's "enemy alien" status alone was tantamount to probable cause, effectively suspending the Fourth Amendment protection from unreasonable search and seizure. Under this decree, search warrants could be obtained without any showing of suspicious activity or evidence of a crime. Authorities in New York City and elsewhere raided more than 2,900 homes of Italian immigrants who did not hold American citizenship. They seized flashlights, cameras, binoculars, firearms and short wave radios.