SANTA ANA (CNS) - Homeless advocates will square off in federal court Tuesday against officials from Orange County, Anaheim, Costa Mesa and Orange to prevent them from enforcing anti-camping laws along the Santa Ana riverbed and in the surrounding cities.

The advocates want a preliminary injunction preventing Orange County from evicting transients from the Santa Ana riverbed. Last week, U.S. District Judge David O. Carter granted a temporary restraining order when county officials made it clear to the plaintiffs who brought the suit that they intended to begin enforcing anti-camping and trespass laws along the riverbed.

On Monday, the National Law Center on Homelessness and Poverty filed a letter with the court in support of Orange County Catholic Worker, the nonprofit that filed the lawsuit against the county and cities. The center said it has ``spent years analyzing how government policies and practices impact homeless persons and their constitutional rights, as well as researching constructive alternatives to the criminalization of homelessness.''

The Washington, D.C.-based organization said it has established a list of principles and practices in a ``Tent City, USA'' report that provides suggestions to municipalities struggling with homeless encampments. The primary principle is that everyone must have a ``safe, accessible, legal place to be, both at night and during the day, and a place to securely store belongings -- until permanent housing is found.''

Orange County Catholic Worker argues that evicting the transients will disperse them to the surrounding cities, where they will be cited for trespassing, loitering and anti-camping laws.

The center said officials in Charleston, South Carolina, cleared out an encampment of 100 or more transients without an arrest. Officials in Indianapolis and Charleston, West Virginia, provided alternative housing for transients in encampments before clearing the areas out as part of court settlements, the center reported.

``The only true remedy for this constitutional ill (of criminalizing homelessness) is to provide housing, so that no one needs to sleep or conduct other basic, life-sustaining conduct on the streets in the first place,'' the center's attorney, Eric S. Tars, wrote in Monday's letter.

Orange County Catholic Worker argued in its brief that county officials have failed for years to provide affordable housing for the area's needy and that its homeless shelters are overcrowded.

Orange County officials, however, say they have plenty of beds available. The problem, they say, is that many transients have refused outreach services, choosing to live on the streets rather than abide by the rules at shelters, such as abstaining from drugs and alcohol.

Orange County Board Chairman Andrew Do said officials have been reaching out to the transients for the past six months, advising them that they must leave eventually and offering them a variety of services.

``At no time during this process have we ever run out of capacity in terms of beds available immediately to the residents of the riverbed, so, frankly, I don't know why Judge Carter did not wait until the hearing on Tuesday so he would be fully informed of the circumstances,'' Do said after Carter issued a temporary restraining order last week.

Orange County Supervisor Shawn Nelson said the trash piling up along the riverbed has caused its own set of problems.

``There's an environmental risk that seems to be getting ignored here,'' Nelson said.

``We've removed over 100 tons of trash there,'' he said. ``This thing has gotten out of hand. They've built fortresses, walls, barriers, and stacks of debris.''

Nelson noted that he argued for setting up a temporary shelter with showers and toilets in the Orange County Great Park area in Irvine but was rebuffed.

``I've offered alternatives that were better. I didn't win,'' Nelson said.

Supervisor Todd Spitzer added: ``I'm worried we're going to start getting in the world of judicial activism.''