Philip Berrigan, 79, a pacifist, writer and iron-willed advocate for peace whose nonviolent protests against militarism led to repeated imprisonments, died of cancer Dec. 6 at his home in Baltimore.

For nearly four decades, Mr. Berrigan, a former Roman Catholic priest, was a major figure in the American peace movement, with his stature bolstered by his willingness to endure long prison stretches in county, state and federal cells.

Believing, as did Martin Luther King Jr., that "war is our government's number one business," Mr. Berrigan began his dissent against military violence in 1967, when he and three others destroyed draft records in a government office in Baltimore. In 1968, he and another group struck again at a Catonsville, Md., selective service facility, where hundreds of draft records were burned with homemade napalm.

Arrested and convicted, he was the first American Catholic priest to be jailed for political dissent, according to one biographer. He later escalated his high-stakes protests by furtively entering military bases to do symbolic damage to warplanes, bombs and other weapons of mass destruction.

What juries and judges perceived as lawbreaking -- being "a danger to the community" said a North Carolina judge in 1993 -- Mr. Berrigan saw as allegiance to international treaties forbidding nations to prepare for wars of annihilation.

In time, large numbers of pacifists, modeling themselves after Philip Berrigan, would engage in similar antiwar actions. Collectively, they became known as the Plowshares Movement, a loosely organized coalition credited with more than 80 separate actions that almost always resulted in jail terms. Nuns and priests were among those locked up.

Whether by himself or with legal help from such human rights lawyers as Ramsey Clark and William M. Kunstler, Mr. Berrigan argued to judges "the necessity defense."

In "Fighting the Lamb's War: Skirmishes with the American Empire," his 1996 autobiography, Mr. Berrigan writes: "If a house full of children is burning, it is necessary to break the door down to rescue them. [In our trials] the government refused to allow the necessity defense, arguing that we could not prove that nuclear war was imminent. We explained that nuclear war could happen at any time. It was imminent because the government was designing, building and deploying nuclear weapons. It was imminent because our air, water and food supply were being poisoned with radioactive isotopes. All weapons, nuclear and conventional, reflect the spirit of murder, rather than of hope."

At a Pennsylvania trial in 1981, the judge snapped: "Nuclear warfare is not on trial here. You are."

Through the late 1990s, Mr. Berrigan, a sturdily-built, gregarious man, accumulated more than a dozen years of prison time, including federal stints in Danbury, Conn., and Lewisburg, Pa.

His methods of resistance often drew criticism. From the right, he was ridiculed as a professional prisoner whose actions had no effect on public policy. Some on the left said that his destroying of property -- damaging weapons, burning draft records -- was itself a form of violence.

"It is a curious argument," Mr. Berrigan wrote, "one I've heard many times. Warheads whose sole purpose is to vaporize cities are hardly to be thought legitimate property. Bombs that indiscriminately murder millions of men, women and children are not 'property.' "

The youngest of six brothers in a Syracuse, N.Y., Irish, Catholic household, Mr. Berrigan enthusiastically joined the Army during World War II. As an infantry officer, "I was a highly skilled young killer. I thought that's what patriots do. God may tell us not to kill, but when the state calls, we must obey. We must become remorseless killers, willing to use any means to defend against the enemy."

His conversion to nonviolence was years ahead.

After the war, and a degree from Holy Cross College, Mr. Berrigan studied for the priesthood in the Josephite order. Following his ordination in Washington in 1955, he served for a year in an impoverished parish in Anacostia.

In 1957, he was sent to New Orleans, where he taught theology for seven years in an all-black parish high school. It proved to be a radicalizing experience: "I set out to discover why my black parishioners lived in ghettos, why their children attended all-black schools, why hospitals refused black patients, why the police routinely beat and even killed black citizens. And the quest always returned to the same poisonous tree [of racism], the roots of which were strangling our nation's soul."

By the mid-1960s, and now serving in a Josephite parish in Newburgh, N.Y., he was ordered by his superiors to stop speaking out against injustice: "I was told, quite literally, to shut my mouth."

He declined.

In 1970, at 43, he married Elizabeth McAlister, a member of the Religious Order of the Sacred Heart. Because he was a priest and she a nun, the couple at first did not make their union known publicly. When they did, in 1973, both were immediately excommunicated by the Catholic church. Eventually Mr. Berrigan, gifted with Irish wit, would describe himself as "a Catholic trying to become a Christian."

The couple settled in a Baltimore working-class neighborhood. They called their home Jonah House, one that soon became a communal haven for prayer meetings, antiwar strategizing and students looking for guidance in simple living. Mr. Berrigan earned a modest income from house painting, lecturing and writing.

Among the regular visitors to Jonah House was the Rev. Daniel Berrigan, a Jesuit priest and Philip's older brother. The two were soul mates and, often enough, cellmates. Linguist and political dissident Noam Chomsky called the two brothers "heroic individuals, willing to do what many realize should be done, regardless of the personal cost, with a simplicity of manner. There are not too many people of whom this can be said."

Away from the barricades, Philip Berrigan was known less as a resolute defier of state and church power than as a person of deep compassion, faith and generosity.

Actor Martin Sheen, a friend, described Mr. Berrigan as "a Christian who truly walks the radical way of the cross. [He] overturns the tables of injustice and summons us to love our enemies and worship the God of peace. Like Thoreau, Gandhi, King and [activist and journalist] Dorothy Day, Phil Berrigan exemplifies courage. He is both an inspiration and a challenge to me and countless others."

Books by Philip Berrigan include "The Catholic Church and the Negro" (1962), "No More Strangers" (1966), "A Punishment for Peace" (1969), "Prison Journals of a Priest Revolutionary" (1970), "Widen the Prison Gates: Writings from Jails, April 1970-December 1972" (1973), "Whereupon to Stand: the Acts of the Apostles and Ourselves" (1993) and, with Elizabeth McAlister, "The Time's Discipline: the Beatitudes and Nuclear Resistance" (1993).

In addition to his wife and brother Daniel, survivors include three children and three other brothers.

Philip Berrigan was the first American Catholic priest jailed for political dissent. Followers who engaged in similar antiwar actions became part of the Plowshares Movement.