Retired Supreme Court Justice Harry Blackmun, author of the 1973 decision that legalized abortion nationwide and set off one of the most explosive political debates in American history, died at age 90. Justice Blackmun served 24 years on the nation's highest court after being appointed in 1970 by President Nixon. He retired in 1994. Justice Blackmun died at Arlington Hospital in suburban Arlington, Va., from complications after hip-replacement surgery. He had fallen and broken his hip at home a day before the operation. The lifelong Republican was considered a staunch conservative in his early days on the court. By the time he retired, he was considered its most liberal justice, but he told friends the court's politics had changed more than his own.

Justice Blackmun often cast liberal votes in cases pitting individual liberties against governmental authority. But he generally voted against expanding the rights of criminal suspects. He was a champion of maintaining a strict separation between church and state. But towering above all else in his high-court tenure was his role in the 1973 decision and subsequent abortion rulings. His authorship of Roe vs. Wade made him the most vilified Supreme Court member in history. He received more than 60,000 pieces of "hate mail" because of the decision. The letters called him a murderer and a butcher. They compared him to the Nazi overseers of genocide. Justice Blackmun insisted on reading all such mail. "I want to know what the people who wrote are thinking," he once said. In a 1983 interview with The Associated Press on the eve of his most famous decision's 10-year anniversary, he repeated the phrase "author of the abortion decision" slowly and softly. "We all pick up tabs," he said. "I'll carry this one to my grave."

After years of stopping just short of reversing Roe vs. Wade, the court in 1992 reaffirmed, by a 5-4 vote, the 1973 ruling's central holding: that women have a constitutional right to end their pregnancies. A triumphant Justice Blackmun wrote that the victory was good law only as long as the current court was intact. But President Clinton's election and Justice Byron White's decision to retire before Blackmun lessened the anticipated impact that Justice Blackmun's departure would have on legalized abortion. When appointing Justice Blackmun, Nixon called him a "strict constructionist," a term defined by Nixon aides as a judge who leaned toward interpreting existing law rather than making new law. He was Nixon's third choice to fill the vacancy created when Justice Abe Fortas resigned under fire for having accepted a $20,000 fee from the family of a financier who went to prison. The Senate rejected Nixon's nominations of two federal appeals-court judges, Clement Haynsworth of Greenville, S.C., and G. Harrold Carswell of Tallahassee, Fla. Justice Blackmun, who had been a member of the 8th U.S. Circuit Court of Appeals since 1959, was confirmed by a unanimous Senate vote.

In his early years on the high court, he was derided for what legal scholars perceived as his dependence on fellow Minnesotan and longtime friend Warren Burger, who had been appointed to the court by Nixon a year earlier. Burger later became chief justice. Justice Blackmun was called "Hip Pocket Harry" and "The Minnesota Twin" in print. But by the end of his first decade on the court, he had established himself as an independent force whose vote often was a critical one in close cases. Justice Blackmun also emerged in a new role: the justice most intent on forcing the court to come to grips with the realities of the problems it was asked to resolve and with the real-world effects of those resolutions. His opinions often portrayed those realities with passionate rhetoric. When the court in 1993 ruled that U.S. authorities need not give hearings before seizing and returning Haitians who had fled their homeland by boats, Justice Blackmun was the lone dissenter. "They demand only that the United States, land of refugees and guardian of freedom, cease forcibly driving them back to detention, abuse and death," he wrote. "That is a modest plea . . . We should not close our ears to it."

When the court in 1989 disallowed a battered boy's lawsuit against the child-custody officials who placed him with his abusive father, he again dissented. "Poor Joshua," he wrote. "Victim of repeated attacks by an irresponsible, bullying, cowardly and intemperate father and abandoned by (officials) who placed him in a dangerous situation." Months before his retirement, Justice Blackmun repudiated his career-long acceptance of capital punishment and declared himself opposed to the death penalty in all circumstances. "The death-penalty experiment has failed. I no longer shall tinker with the machinery of death," he wrote. He wrote for the court when it ruled in 1985 that Congress has almost unlimited power to force state and local governments to comply with federal laws - including those requiring overtime pay for more than 40-hour work weeks. He also wrote the 1991 decision that said employers may not bar women from certain hazardous jobs just to protect fetuses. A 1984 opinion he wrote required states to offer "clear and convincing" evidence of parental unfitness before permanently severing all parent-child ties.

In a 1977 decision, he wrote for the court that a blanket ban on lawyer advertisements violated free-speech rights. Justice Blackmun was born in Nashville, Ill., but was raised in St. Paul and Minneapolis. He and Burger first met as kindergarten pupils. Their friendship was long lasting, and Blackmun served as best man in Burger's 1933 wedding. But on the high court, differences between the two jurists strained those boyhood ties. Justice Blackmun won a scholarship to Harvard, where he earned highest honors as a mathematics major. He then went to Harvard's law school. After practicing law in the Twin Cities for nearly 20 years, Justice Blackmun served as general counsel of the Mayo Clinic in Rochester, Minn., from 1950 to 1959. President Dwight Eisenhower appointed him to the 8th U.S. Circuit Court of Appeals that year. He is survived by his wife, Dorothy, and three daughters.