BOB ABERNETHY: The issue of what to do about the homeless is back in the public eye, as cities around the country have begun cracking down on them. The poor, the mentally unstable, and the drug addicted are often lumped together as a public nuisance, not always deserving of charity, it's thought, even in cities considered havens for the homeless. Critics of the crackdown call it criminalizing homelessness, and argue that society has a moral obligation to care for the afflicted.

From San Francisco, Barbara Rodgers reports.

BARBARA RODGERS: In cities around the country, the number of homeless appears to be rising, despite a booming economy. But as the numbers climb higher, compassion seems to be running low, even in a city like San Francisco, known for its liberal attitudes.

Ms. CANDACE LOW: It's about empathy, and I think the more economically comfortable you become, the less you can understand people being on the streets.

RODGERS: Public impatience with panhandlers, addicts, and littered streets has led to a get-tough policy.

Reverend AMOS BROWN (City Supervisor): We're concerned about a safe, clean, orderly city.

RODGERS: City Supervisor Amos Brown is also a Baptist minister, whose church runs a weekly soup kitchen. The time has come, he says, to balance compassion with public responsibility.

Rev. BROWN: There's a difference between being homeless and being a street dweller. A street dweller hangs out on the streets and feels that he or she can engage in any conduct, at any time, at any place, even though that conduct may impact on the quality of life for others.

RODGERS: It's not just San Francisco that seems to be pulling in the welcome mat for the homeless. In at least 50 cities across the country, there are now laws on the books designed to keep people from living on the streets.