While an instructor at Marymount College, McAlister got involved with peace demonstrations and prayer vigils against the Vietnam War. Through this community, McAlister met Philip Berrigan, who came to speak and demonstrate in Tarrytown, New York. According to McAlister's daughter, Frida Berrigan, the two met "at a funeral in 1966", although there are accounts that Berrigan and McAlister moved in the same circles from 1964, on. In early 1969, Phil Berrigan and McAlister married by "mutual consent". At this time, Berrigan was awaiting sentencing for pouring blood on draft files in the US Customs House in Baltimore.
While Berrigan was in federal prison for his involvement in the Catonsville Nine, McAlister and Berrigan communicated via a fellow inmate, Boyd Douglas, who was allowed furlough for work release. Douglas was an informant for the Federal Bureau of Investigation, and turned over the contents of Berrigan and McAlister's letters to the authorities. These letters, which included nascent plans to kidnap Henry Kissinger, led to the prosecution of McAlister, Berrigan, and five others, known as the Harrisburg Seven.
Excommunication and marriage
Berrigan had spoken and written about the importance of celibacy to activists, but abandoned his previous position against romantic entanglements for McAlister. McAlister and Berrigan were married in January 1972 while Berrigan was in prison. Following his parole, on May 28, 1973, they were legally married and they were excommunicated by the Catholic Church. McAlister had three children with Berrigan: Frida, Jerry, and Kate. McAlister and Berrigan continued their activism, serving jail time for their civil disobedience. During their twenty-nine year marriage, Berrigan and McAlister spent a total of eleven years separated by prison.
McAlister and Berrigan founded Jonah House in 1973. Called a resistance community Jonah House was a commune, with the Berrigan-McAlister family living in the basement of the Baltimore row house. They raised their three children there, with the help of the other activists in the community. In 1996, Jonah House moved to a house overlooking St. Peter's Cemetery, and the community members cared for the grounds. DePaul UniversitySpecial Collections and Archives holds collections of papers and ephemera, donated by Berrigan family members and friends. These collections include news clippings related to McAlister's life and protest actions, as well as personal letters written by McAlister. The Berrigan Library includes McAlister's personal books, some annotated in her hand.
On April 4, 2018, McAlister and six other people entered the base and performed symbolic acts of disarmament. October 24, 2019 McAlister was convicted on four counts in federal court in Brunswick, GA for entering and holding a symbolic disarming of the Trident submarine’s nuclear weapons. The seven defendants, as of October 2019, face a possible 20 years in prison. Other defendants were Clare Grady, Martha Hennessey, Carmen Trotta, Patrick O’Neill, Fr. Steve Kelly, SJ, and Mark Colville
