John C. Lowe, lawyer. (Dan Addison/University of Virginia Communications)

John C. Lowe, a lawyer who filed suit to overturn the University of Virginia's male-only undergraduate admissions policy, and who later won a landmark First Amendment case and defended the longest-held U.S. prisoner of war in Vietnam against charges of desertion, died Oct. 15 at his home in Bethesda, Md. He was 80.

The cause was heart disease, said his daughter-in-law, Catherine Lowe.

Mr. Lowe had a law practice in Charlottesville in 1969, when he asked his young office assistant, Virginia Scott, about her college plans.

"I guess you will be going to Virginia," he recalled in September to a university news website, UVA Today.

"No," Scott said. "Women aren't allowed at Virginia."

"It shocked me," Mr. Lowe said. "I said, 'Well, then, we'll just have to take care of that.' "

He was a graduate of the university's law school, where some of his classmates were women. He did not realize that, with rare exceptions, women were not allowed to enroll as undergraduates at the public, taxpayer-supported institution unless they were training to be teachers or nurses.

Mr. Lowe asked the university's board of visitors to correct the inequity but was rebuffed. With the assistance of the American Civil Liberties Union and another lawyer, Philip Hirschkop, he filed suit in federal court on behalf of Scott and three other women, Nancy Anderson, Nancy Jaffe and Jo Anne Kirstein.

As early as the 1890s, there had been demands for women to be accepted on an equal footing with men at U-Va. The university's school of education had offered summer courses for women since 1907 — one of the program's early students was artist Georgia O'Keeffe — and women had been admitted to graduate and professional programs since 1920.

Yet half a century later, it was all but impossible for a woman to receive a bachelor's degree from the university's College of Arts and Sciences. By contrast, the state-supported College of William & Mary in Williamsburg began admitting women in 1918.

Mr. Lowe filed a discrimination lawsuit against what he called his "beloved university" in federal court in Richmond. The judge, Robert R. Merhige Jr., issued a temporary injunction allowing Scott and the other women to enroll while the case was being considered.

The 6-foot-5 Mr. Lowe "was a tall, loud-voiced guy who could really dominate a courtroom," his former law partner J. Lloyd Snook III said Thursday in an interview.

Mr. Lowe's courtroom opponent was his first boss after law school, James Harry Michael Jr., a former state senator.

"It's like a class-C movie plot," Mr. Lowe told UVA Today. "It's David and Goliath; it's the mentor and the protege."

At a hearing in 1970, Michael argued women would require daintier desks in classrooms and noted that there were few women's restrooms in campus buildings.

Mr. Lowe called on one of his witnesses, feminist writer Kate Millett, who died last month, to respond: "Senator, all you do is plant geraniums in the urinals and you've got a women's bathroom."

Mr. Lowe also produced a minority report, suppressed by a university committee, recommending women be admitted as students.

Under threat of a federal court ruling, the U-Va. governing board agreed to admit 450 women in 1970 and 550 the next year. By 1972, all restrictions on the admission of women were lifted.

Scott, Mr. Lowe's onetime assistant, graduated in 1973 and later received two master's degrees from the university.

"He was brilliant, fearless and totally dedicated to equal rights cases," she told UVA Today, "regardless of how unpopular it made him."

In other cases, Mr. Lowe defended dozens of people arrested during a 1970 antiwar protest at the university. They were charged with violating Virginia's unlawful assembly act, popularly known as the "riot act," in which any group of more than two people could be charged with a crime. Mr. Lowe successfully argued by the Supreme Court of Virginia that the law was a violation of free speech.

After the 1973 siege at Wounded Knee, S.D., in which two FBI agents were killed during a standoff with American Indians, Mr. Lowe helped win an acquittal for one of the defendants.

Mr. Lowe also defended Jeffrey C. Bigelow, the managing editor of a weekly newspaper in Charlottesville, in a case that reached the U.S. Supreme Court in 1975. Bigelow had published an advertisement for abortion services in New York in defiance of a Virginia law. Mr. Lowe won a landmark decision, by a 7-to-2 vote, that established First Amendment protection for commercial speech.

"John was an interesting paradox," Snook, his onetime law partner, said. "He was a conservative Republican, but he was associated with all these liberal causes. He really saw the law as a noble calling and as a way to improve the lot of people as individuals."

John Christian Lowe was born Dec. 3, 1936, in Allentown, Pa. His father was a business executive who later moved the family to South Hill, Va., and Manhasset, N.Y.

Mr. Lowe received a bachelor's degree in chemistry in 1957 from Lehigh University in Bethlehem, Pa., then served in the Army for seven years, reaching the rank of captain. He followed his younger brother to law school at the University of Virginia, graduating in 1967.

Through the years, Mr. Lowe handled many pro bono cases, including the controversial defense of Robert R. Garwood, a Marine captured in Vietnam in 1965 at age 19 and held prisoner for 14 years.

He was the longest-serving POW of the war and the only one charged with desertion and collaboration with the enemy.

Fellow Marines denounced Garwood as a traitor.

Mr. Lowe mounted one of the first cases using post-traumatic stress syndrome as a defense, arguing that Garwood was driven insane by his years in captivity.

"He was subjected to torture, deprivation, and inhumanities almost too indescribable to believe, resulting in his becoming profoundly mentally ill," Mr. Lowe said during a 1981 court-martial at Camp Lejeune, N.C.

The jury of five Marines convicted Garwood of communicating with the enemy and striking a fellow prisoner, but he was exonerated of the most serious charges of desertion and soliciting other troops to lay down their arms in the face of the enemy. Garwood was given a dishonorable discharge and set free.

In 1992, Mr. Lowe joined the Washington firm of Finnegan, Henderson, Farabow, Garrett & Dunner, where he handled patent infringement trials. He had a private practice from 2003 until his death.

His marriages to Anne Muir and Constance Anthony ended in divorce. Survivors include a son from his second marriage, Christian Lowe of Bethesda; a brother, retired federal magistrate judge David G. Lowe of Richmond; and two grandchildren.

Mr. Lowe remained closely attached to the University of Virginia, where he taught courtroom advocacy at the law school for many years. He frequently attended football games and was present at an Oct. 6 ceremony honoring the university's 200th anniversary.

This fall, women make up 56 percent of U-Va.'s first-year class.

Clarification: An earlier version of this story noted that the University of North Carolina at Chapel Hill had female students in the 1890s. Women were not admitted on an equal basis as undergraduates to all branches of the UNC system until the 1960s.