ST. LOUIS - Pioneering civil rights lawyer Margaret Bush Wilson, a former national chair of the NAACP, died Tuesday. She was 90.

She died at Barnes-Jewish Hospital of multiple organ failure, her son, Robert E. Wilson III, said.

Wilson, whose life passion was being a lawyer, had continued practicing law until June. She was the second black woman to pass the Missouri Bar after graduating from the now-defunct Lincoln University School of Law, a "separate but equal" institution that had been created for blacks in Missouri.

Wilson was born in 1919, one year before women won the right to vote, and broke barriers in her career.

She and her husband, Robert E. Wilson Jr., started a law firm in St. Louis after World War II.

She joined the legal team on the historic Shelley v. Kramer case, which challenged housing covenants that excluded blacks and Jews from neighborhoods in St. Louis and other cities. The case, which came out of her father's real estate dealings, went all the way to the U.S. Supreme Court, which ruled in 1948 that the covenants were unenforceable.

Wilson's mother had helped organize the state NAACP and her father had paid the attorney fees in the Shelley v. Kramer case.

After presiding over the city and state NAACP, Wilson became the first black woman to head the national NAACP board for nine terms starting in 1975.

She served as U.S. attorney for the Rural Electrification Administration and assistant attorney general in Missouri.