Rita Charmatz Davidson, a champion of liberal causes who became the first woman appointed to Maryland's highest court, died of cancer Nov. 11 at her home in Chevy Chase. She was 56 and had been ill for several months.

Judge Davidson, a Brooklyn-born lawyer educated at Yale, served on a variety of Montgomery County and state government agencies in a career that spanned nearly 25 years. In addition to being the first woman appointed to the Maryland Court of Appeals, a distinction she earned in 1979, she was also the first woman named to a Maryland governor's Cabinet. Former governor Marvin Mandel named Davidson his secretary of Employment and Social Services in 1970.

"She contributed much to the state of Maryland, not only through her long and honorable service as a judge, but through her courageous insistence on performing that service to the very end," Gov. Harry Hughes said in a statement yesterday.

Whether serving as a member of Montgomery's planning board or issuing strongly worded dissents from the generally conservative Court of Appeals, Judge Davidson was "a strong, effective political force," said Charles W. Gilchrist, Montgomery County executive.

Judge Davidson, an outspoken, articulate woman who helped craft appeals court rulings on issues ranging from the death penalty to cameras in the courtroom, began her law career just as the women's liberation movement emerged a generation ago.

The daughter of Russian immigrants, she graduated from Goucher College in Maryland in 1948 and went on to Yale Law School, where she graduated in 1951. Her goal of becoming a lawyer came early in her life.

"When other little girls were saying they wanted to be nurses or teachers or mommies, I was saying I wanted to be a lawyer," Judge Davidson said in a 1978 interview. "I knew it was also a good thing to be a judge."

After earning her law degree, Judge Davidson moved to the Washington area and entered private law practice with the D.C. firm of Liebick and Weyand. She also became active in Democratic politics in Montgomery County and served on the county's board of appeals, planning board, and as Montgomery's first zoning hearing examiner.

Between 1972 and 1979, Judge Davidson served on the Court of Special Appeals, Maryland's second highest tribunal, where she helped shape important decisions affecting administrative law, product liability and criminal procedures.

Blair Lee III, the former acting governor of Maryland who appointed Judge Davidson, said he named her to the court not only because "the time had come to have a woman on the bench" but because she was "a true legal scholar."

Judge Davidson is survived by her husband and law school classmate, David Davidson, deputy chief administrative law judge on the National Labor Relations Board; a daughter, Minna, of Silver Spring; a son, Leo, of New Haven, Conn.; her mother, Eiga Charmatz of New Hyde Park, N.Y.; her sister, Dr. Isabel Zackson, also of New Hyde Park, three nieces and a nephew.