Robert L. Thoburn was a fundamentalist Presbyterian clergyman, conservative Virginia legislator, founder and proprietor of the Fairfax Christian School, and an author.

He espoused a less-is-best philosophy of government, arguing in one of his books for “the eventual abolition of all public schools.” Starting in the late 1980s, Mr. Thoburn fought a decade-long and ultimately unsuccessful legal battle with Fairfax County over whether local zoning ordinances should apply to his school.

He contended that the facility was exempt from local land-use regulations because it was a religious institution.

From 1978 to 1980, he served in the Virginia House of Delegates as a Republican. He often voted against measures considered dear to his Northern Virginia constituents, such as a 1-cent sales tax to support Metrorail and the creation of a law school at George Mason University. They would only lead to more governmental regulation, he said, admitting that “I take positions that are considered suicidal.”

Mr. Thoburn, 83, died Dec. 23 of cancer at his home in Vienna. His son, John Thoburn, confirmed the death.

Robert Loren Thoburn was born May 19, 1929, on a farm in Harrisville, Ohio, and was one of 11 children. As a high school teenager, he plowed the fields behind a team of horses while his older brothers served in the military during World War II.

In 1951, he graduated magna cum laude from what is now Muskingum University in New Concord, Ohio. He received master’s degrees in divinity and theology in 1955 at Westminster Theological Seminary near Philadelphia, and he was ordained that same year at Orthodox Presbyterian Church in Philadelphia.

He came to the Washington area in 1959 and, two years later, he opened the Fairfax Christian School on the ground floor of a large Victorian home and ran it as a business instead of a nonprofit corporation, The Washington Post reported.

Initially, the school offered pre-kindergarten through grade eight. As enrollment expanded, upper grades were added. The first high school class graduated in 1968. That year enrollment reached its peak at 650. Current enrollment is 200.

The school’s legal battles with Fairfax County commenced in 1988, when Mr. Thoburn and members of his family tried to open a campus on a 29-acre site near Reston. County officials argued that the site was zoned for residential use.

The Thoburns maintained that First Amendment guarantees of religious freedom trumped local zoning laws, an argument that the Virginia Supreme Court refused to hear.

In following years, there were various compromises and temporary sites for the school.

It’s now at a 28-acre site in Vienna. Mr. Thoburn served as its headmaster until 2001 and taught government, history and free-market economics until retiring fully in 2009.

He wrote a 1975 book, “How to Establish and Operate a Successful Christian School,” based on his own experience. On its Web site, the Fairfax Christian School said Mr. Thoburn had helped start more than 200 Christian schools in the United States.

In his 1986 book, “The Children Trap,” Mr. Thoburn argued for the abolition of public schools, which he wrote were run by “humanist kidnappers (who) . . . have used the tyranny implicit in compulsory education to indoctrinate the children of Christians.”

He also wrote a 1984 book, “The Christian and Politics,” in which he argued that religious faith should be applied to every aspect of life and urged Christians to become active in politics.

In his own political life, Mr. Thoburn ran unsuccessfully for the U.S. House of Representatives in 1976 and 1978 and for a seat on the Fairfax Board of Supervisors in 1987. His election to the Virginia House of Delegates in 1977 was his only successful bid for public office.

As a delegate in Richmond, Mr. Thoburn was widely known as the most conservative member of the legislature. He was an opponent of the Equal Rights Amendment. He supported the execution of rapists and said he believed that men who seduce women should be compelled to marry the woman — if the woman’s father agreed.

Survivors include his wife of 60 years, Rosemary Sweet Thoburn of Vienna; eight children, David L. Thoburn and John M. Thoburn, both of Vienna, Mark A. Thoburn of Mission Viejo, Calif., Lloyd L. Thoburn of Boyds, Md., Robert L. Thoburn II of Chantilly, Jonathan D. Thoburn of Reston, Ruth Shade of Carbondale, Ill., and Mary Fusaro of Stephens City, Va.; a brother, Carl Thoburn of Ashburn; a sister, Jean T. Rinkes of Cadiz, Ohio; a half-sister, Karen T. Russell of Dellroy, Ohio; 46 grandchildren; and 19 great-grandchildren.