The Plowshares Movement is a (primarily) Christian pacifist movement begun in the 1980’s. Its focus is on the elimination of nuclear weapons and it uses non-violent direct action and civil disobedience to draw attention to its goals. The group has its origins in the Catholic Left more broadly and the Catholic Worker movement in particular.
Origins: Dorothy Day and the Catholic Worker Movement
Dorothy Day was the founder of the Catholic Workers movement. She was a reporter for a socialist newspaper who converted to Catholicism. She retained many of her pre-Catholic political beliefs, including her concern with poverty and support for organized labor.
After her conversion she began publishing her own newspaper, The Catholic Worker. Her paper combined her support for labor with Catholic religious teaching. She also founded a series of hospitality houses to provide shelter and aid to the poor.
Day’s Catholicism was based on more than charity, and emphasized the need for personal sacrifice and political transformation to ease social ills. She advocated for her followers to withdraw from violent and exploitative social arrangements, and to resist and confront those who perpetuate them. The Catholic Worker Movement opposed capitalism and militarism and engaged in civil disobedience to challenge both.
Day’s opposition to a mandatory New York City nuclear drill was an example of the kind of protest that prefigured the Plowshares Movement. The drill, first conducted in 1955, required the cooperation of the city’s residents with a threat of a year in prison for non-compliance. Objecting to what was seen as an attempt to normalize the possibility of nuclear war, Dorothy Day and other movement supporters gathered in City Hall Park to protest and were arrested.
This protests continued every year growing little by little, until in 1961 more than 2,000 people gathered in the park in solidarity with the protesting Catholic workers. Recognizing that their nuclear attack drills were being ignored, the New York City government bowed to the protest pressure and discontinued them.
Phil and his brother Daniel Berrigan both belonged to the same militant left strand of Catholicism and engaged in non-violent civil disobedience to protest the Vietnam War. As the war dragged on, they began to use more dramatic tactics.
In October 1967, Phil Berrigan and three others (Tom Lewis, Minister Jim Mengel, and poet Dave Eberhardt) raided a Selective Service office in Baltimore and poured blood over the draft files. They invited members of the local press to come along with them to draw greater attention to the action. Berrigan explained to the press “This sacrificial and constructive act is meant to protest the pitiful waste of American and Vietnamese blood in Indochina.” After they’d finished, the four waited patiently for the police to arrive and arrest them. The local police arrived within minutes, but waited for federal agents to arrive to take the men into custody.
Berrigan faced a hostile audience from local newspapers and his own church. The American Catholic Church at the time was generally supportive of the war, while local papers like the conservative leaning Baltimore New American denounced the protestors. After their appeals failed, the Baltimore four were sentenced on May 24, 1968; Berrigan and Lewis were given six years in prison, Eberhardt three, and Mengel was released on his own recognizance and never served any prison time for his role in the protests. 
While on bail awaiting sentencing, Berrigan became involved in another similar protest action, this one planned by George Mische. 
Mische was inspired by the earlier action and the subsequent press coverage of the trial. He took note of how the prosecution had overbuilt its case to try and get tougher penalties against the Baltimore four, and had inadvertently revealed a weakness of the draft system. To try and prove that the four had done more than 5,000 dollars in damages (a requirement for one of the charges), the prosecution revealed that there were no backups of the records held at the draft offices. Mische got the idea that instead of defacing draft records protestors ought to destroy them. 
Mische recruited Thomas Melville and Marjorie Bradford (former Catholic missionaries in Guatemala who were removed from their work for meeting with guerillas) Mary Moylan (a nurse who’d worked in Uganda for a Catholic run hospital, and had also quarreled with the church over how the hospital was run) John Hogan (another Catholic who’d worked in Guatemala and also became opposed to US policy) for his planned action. Tom Lewis and Phillip Berrigan of the Baltimore four also joined them.
Phillip Berrigan was able to convince his brother Daniel to join the planned protest. Daniel had already faced retribution from within the Catholic hierarchy over his positions on the Vietnam War. In 1965, Cardinal Francis Spellman had chewed him out over comments Daniel had made about burning draft cards. He also ran into trouble with Cardinal Spellman when he spoke at a memorial service for Roger Laporte, a young Catholic who set himself on fire in front of the UN building to protest the Vietnam War. To punish Berrigan, Cardinal Spellman sent him away to South America for two years.
In May of 1968 after a visit by his brother Phillip, Daniel agreed to join the protest.
The nine raided another Selective Service office in Maryland. They took conscription files, and burned them with homemade napalm from a recipe found in a Special Forces handbook. Supporters who were not involved in the raid, but had helped prepare the napalm and drove the nine to the draft board, mailed press releases when they saw the flames. 
The nine were tried in federal court in October 1968. The day the trial began a demonstration organized by the Baltimore Defense Committee (a group formed to aid the nine during their trial) drew around 1,400 demonstrators. In response to the planned protest the city brought in 800 more police officers effectively doubling the size of their police force.
Officers who confronted the protestors were decked out in full riot gear, including gas masks, riot helmets, riot batons, and German shepherds. Some also illegally removed their name tags, but despite their readiness for a confrontation with the protestors no violence occurred. 
The nine were convicted on November 8, 1968 and their sentences ranged from two to six years (In Phillip’s case to run concurrently with the six year sentence he’d received from the Baltimore protest.) When their final appeals ran out in 1970 four of the Catonsville Nine, joined by one of the Baltimore Four decided to go into hiding rather than surrender themselves to a government they thought was committing mass murder. 
During their brief time on the run in 1970, Daniel and Phillip Berrigan were placed on the FBI’s Most Wanted list, despite the fact the two had never committed a violent crime, and were both avowed pacifists. They were apprehended the same year; Philip Berrigan along with fellow fugitive Eberhardt were apprehended by FBI agents at the rectory of St. Gregory’s in Manhattan, where they were planning to attend a peace rally. Daniel Berrigan was apprehended in August at the home of William Stringfellow, on Block Island, R.I.
While in prison, the Berrigan brothers linked up with existing networks of peace activists and war resisters already in the prison system and continued their non-violent protest methods, fasting to protest the war, and refusing to work in war related industries in the prison.
Phil Berrigan was released in 1973, and returned to Baltimore, Maryland where he married fellow Catholic left activist Elizabeth McAlister. Together with other Catholic left activists, they formed a religious community called the Jonah House. 
The Jonah house was similar to the hospitality houses founded by Dorothy Day, and emphasized non-violence and voluntary poverty. In addition, the Jonah House placed special emphasis on anti-war activism, leading to the group’s later participation in the anti-nuclear movement that grew in the 1980’s. 
After the end of the war in Vietnam, members of Jonah House planned protest actions against the nuclear arms race between the United States and the Soviet Union. In 1980 the Berrigan brothers along with six other activists entered a General Electric (GE) plant in Pennsylvania. 
The group came with hammers and four pints of their own blood. They distracted a guard to gain entry to the plant and located two metal nosecones for Mark 12-A missiles, used to guide the warheads to their targets. They beat on them with the hammers and poured blood on the nosecones, blueprints and work orders in the facility. 
The protest was meant to reference a biblical passage in the book of Isaiah:
And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem. And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war any more. (emphasis added)
The original group of 8 activists were arrested and in 1981 convicted of criminal conspiracy and burglary. After a ten year long appeals process the convictions were upheld, and the activists received sentences equal to the time they had already served in jail.
The original plowshares protest has led to similar actions across the planet; since the first protest, more than 80 similar actions have occurred throughout the world.
In 2008 three New Zealand activists (Teacher Adrian Leason, 45, Dominican friar Peter Murnane, 69, and farmer Sam Land, 26) broke into a government spy base near Blenheim and slashed an inflatable plastic dome covering a satellite dish. They admitted to breaking into the base and slashing the dome, but argued in their defense that they did it to try and prevent greater suffering. Specifically they argued that the base was being used to assist the ongoing war in Iraq. They were acquitted of all charges by a New Zealand jury. However a Wellington high court later granted the government the right to seek US$1.2 million for the cost of replacing the dome.
On July 28, 2012, three activists (Sister Megan Rice, 82, Greg Boertje-Obed, 57, and Michael Walli, 63) part of the “Transform Now Plowshares” group, cut through the chain link fence surrounding the Y-12 nuclear weapons production facility In Oak Ridge, Tennessee. They cut through three fences surrounding the Highly Enriched Uranium Materials Facility (HEUMF), and hung up peace banners, and spray painted peace slogans on the HEUMF. They were arrested when security finally arrived the next morning at 4:30 AM.
The three activists were arraigned on July 30, and initially charged with federal trespassing, a misdemeanor with a penalty of up to a year in Jail. However as the story gained greater traction the federal government escalated the charges against them. 
On August 2, when the three appeared in court for a pretrial bail hearing, the prosecution asked that all three be detained until their trial, arguing that the three pacifists were a potential “danger to the community”. The US Magistrate allowed them to be released, and when Sister Megan Rice left the jail she freely admitted to the gathered press that they had indeed broken into the facility, and explained their motivations; that they felt that nuclear weapons posed an existential threat to the survival of the human race, and that their actions were meant to draw attention to the reality of the danger these weapons posed. 
A day after the Magistrate ordered the three released a Department of Energy (DOE) agent swore out a federal criminal complaint against the three for damage to federal property. This was a felony punishable by up to five years in prison. The next week, the charges were again increased this time to three counts. The earlier charge of federal property damage charge was now joined by an additional charge of damage to federal property in excess of $1000 which is punishable by up to ten years in prison. The third charge was for trespassing, a misdemeanor punishable by up to a year in prison. 
The three activists now faced up to 16 years in prison for their non-violent protest. But even still the government continued to escalate the case. On October 4, the three were told that unless the pled guilty to one felony and the misdemeanor charge, the government would add an additional charge of sabotage against the U.S. government.
On December 4, after the three activists refused to take the plea deal, the government made good on its threat and a new indictment was filed. Gone was the misdemeanor trespassing charge. Instead the indictment included the promised charge of sabotage against the United States punishable by up to 20 years in prison, and the two felony property damage charges. In total the three protestors now faced up to 35 years in prison. 
The trial was held in Knoxville in early May 2013. All three took the stand, admitted what they had done, and explained why they did it, But the defense was forbidden by the court “from being allowed to put on any evidence regarding the illegality of nuclear weapons, the immorality of nuclear weapons, international law, or religious, moral or political beliefs regarding nuclear weapons, the Nuremberg principles developed after WWII, First Amendment protections, necessity or US policy regarding nuclear weapons.” as a possible justification for their actions.
The federal manager of Y-12 testified against the protestors alleging that they had damaged the credibility of the site in the U.S. and globally and that their acts had damaged the country’s nuclear deterrence; apparently unable to consider that it may have been the lax security at his base which had done the most harm to the credibility of the site. Regardless the three were convicted on all counts. 
As soon as the jury was dismissed, the government moved to jail the protestors because they had been convicted of “crimes of violence.” When the defense pointed out that all three had remained free since their arrest without incident, prosecution argued that two of the protestors had violated their bail by going to a congressional hearing about the Y-12 security problems, even though the trip had been approved by their parole officers. 
The court sided with the prosecution, and the three were immediately jailed while they await sentencing. In the decision affirming their incarceration, the court ruled that the sabotage and the damage to property convictions were federal crimes of terrorism as defined by congress. Within a few months’ three non-violent protestors who allowed themselves to be arrested without incident and who freely admitted to what they did, were convicted of sabotage and imprisoned as terrorists. Their sentencing is scheduled for September 23, 2013.
 Nepstad, Sharon Erickson “Persistent Resistance: Commitment and Community in the Plowshares Movement” Social Problems, Vol. 51, No. 1 (February 2004), pp. 43-60