The Supreme Court (search) ruled Monday that the government may designate crime-ridden public housing neighborhoods as off limits to visitors and prosecute some trespassers.

Justices for the second consecutive year strengthened the power of housing operators to take extraordinary steps to get rid of crime.

In this case, justices on a 9-0 vote threw out a ruling that a man was wrongly prosecuted for trespassing at a housing complex in Richmond, Va., where his mother and two children live. Because of spiraling crime, streets and sidewalks were designated private property, with signs warning people they faced prosecution for unauthorized visits.

Justice Antonin Scalia (search), writing for the court, said that Kevin Hicks was not engaged in a First Amendment (search) free-speech activity at the complex. He "was not arrested for leafletting or demonstrating without permission," Scalia wrote.

The justice also said that Hicks did not prove that the policy prohibited any substantial amount of protected speech.

The court, however, left open the door for other constitutional challenges against the policy.

Hicks had said he was dropping off diapers when he was arrested in 1999. He had been arrested twice before for trespassing and barred from the complex.

The Virginia Supreme Court had held the 1997 trespassing ordinance was unconstitutional, on the grounds that it harmed people who had legitimate, free-speech reasons for visiting public housing. Justices overturned that decision.

Scalia said that the ordinance did not punish people for their speech.

"The rules apply to strollers, loiterers, drug dealers, roller skaters, bird watchers, soccer players, and others not engaged in constitutionally protected conduct -- a group that would seemingly far outnumber First Amendment speakers," Scalia wrote.

In the other public housing case, the Supreme Court ruled last year that agencies may evict entire families from public housing for drug use by one member.

The Supreme Court had been told in the latest case that poor families were living in the middle of an open air drug market until the policy took effect.

Nationwide, public housing authorities have been striving to combat crime. About 1 million families live in public housing.

"I hope it means the people who run public housing projects will be able to take steps to protect residents from having their homes turned into a crime-infested sewer," said Kent Scheidegger, legal director for the Criminal Justice Legal Foundation.

The case is Commonwealth of Virginia v. Hicks, 02-371.