Advocates for the homeless and the Maryland public defender yesterday testified against legislation that would make it easier to prosecute vagrants.

The proposed bill, filed by Del. James E. McClellan (D-Frederick), would eliminate a 104-year-old law excluding mentally ill persons from prosecution as "tramps." Supporters of the measure told the the legislature's Judiciary Committee that it would simplify court proceedings for local law enforcement officials who arrest and prosecute disruptive vagrants.

The supporters, who included the police chief and state's attorney of Frederick, said McClellan's proposal would eliminate the cumbersome legal requirement that prosecutors prove that insanity was not an element in the misdemeanor offense of being a "tramp."

Under an 1880 Maryland law, tramps are defined as sane persons who "wander about . . . in the open air, without having any lawful occupation."

"If it's a crime to wander in the open air, that's a sad commentary on the criminal justice system," said Alan H. Murrell, the state's chief public defender. "It's an archaic law anyway, one that's not being enforced in any other jurisdiction" outside Frederick, he said.

Frederick Police Chief Richard J. Ashton said his city faces occasional problems with homeless persons. The central Frederick shelter has only 22 beds, yet there are many homeless persons in that city and outlying rural areas, he said.

McClellan's bill "is a vehicle to take them off the street at night," said Ashton, referring to the five or six homeless persons each year whom Frederick police say are disorderly or drunk in public.

But several human services advocates disagreed, saying McClellan's bill is discriminatory and constitutionally vague and would cost localities millions of dollars in increased prison costs.

"It differentially discriminates against the poor and the homeless," said Joanne Selinksi, spokeswoman for a network of homeless shelters in Baltimore. "This would separate those who have from those who have not."

Carol Morrow, a spokeswoman for a coalition of four groups caring for the mentally ill, said some experts estimate that up to 75 percent of the nation's homeless are mentally ill.

In an interview, McClellan said he did not believe his bill would pass in its present form.