In 1976, a construction permit was issued for nuclear reactors on the marshes of Seabrook, New Hampshire, near a heavily populated beach community. On April 30, 1977, the Clamshell Alliance organized a protest on the grounds of these marshes calling for the state of New Hampshire and New England as a whole to be a nuclear-free zone. The 1977 Nuclear Resistance Group on Wesleyan's campus was involved in the April 30 protest. On that day, nearly 2,000 people walked onto the construction site to protest having a nuclear presence in New England. Of those 2,000 people, over 1,400 were arrested and 39 Wesleyan students were among them. In June 1977, the Clamshell Alliance held another on-site rally consisting of 20,000 participants of which several hundred also marched to Washington D.C. to protest in front of the Nuclear Regulatory Commission.

Students at Wesleyan who were arrested on April 30 were charged with criminal trespass in the Portsmouth Court and called for bail solidarity, therefore refusing to post bail until they were all released on personal recognizance. They were held for ten or eleven days, during which Wesleyan's Legal Defense and Bail Fund Board organized a fundraising drive for their release. As of May 11, thirty-two Wesleyan students were still held in state armories apparently under severe conditions; some of those arrested spent 14 hours on a cramped bus before any official arrest and some were held in a room with 691 other people.

Although Wesleyan organized a fundraiser for bail, the imprisoned students felt that it would be counterproductive. One student dictated a letter via telephone asking that the Wesleyan community help in writing letters, making phone calls and protesting the Connecticut governor if he were to accept any of the Seabrook prisoners into Connecticut jails. Some of the arrested students posted bail, and on May 13, the remaining prisoners accepted guilty pleas and were released on their own recognizance.

The Nuclear Resistance Group on Wesleyan's campus continued to stay active in the anti-nuclear front. In 1979, the group participated in another nationally recognized anti-nuclear rally in Buchanan, New York. Over two hundred protesters were arrested, Wesleyan students among them. In the early 1980s, protests were held on campus calling for a nuclear freeze.

The anti-nuclear arms groups also proposed and got approved Wesleyan as a nuclear-free zone. This was achieved in 1984 and consisted of an agreement with Wesleyan students and Wesleyan administration that the school would not participate in the production, testing, deployment, storage, or transportation of nuclear weapons. The school also agreed not to participate in research or investment associated with the development of nuclear weapons. Although this referendum was well-received by the Wesleyan community, the Board of Trustees had the final vote on the implementation of this agreement. Many believed this to be a symbolic gesture of the Wesleyan community during the Cold War, although the agreement was practical in the sense of Wesleyan refraining from investments and research related to nuclear arms. Although Wesleyan still had investments in companies that had some varied involvement in nuclear arms production or research, the campus decided to become a nuclear-free zone like many zoned areas in Europe.