Consensus decision-making, a process in which groups come to agreement without voting, has been a central feature of direct action movements for nearly forty years, from the anti-nuclear movement of the 1970s to the turn-of-the-millennium global justice movement to 2011’s Occupy Wall Street.

Instead of voting a controversial plan up or down, groups that make decisions by consensus work to refine the plan until everyone finds it acceptable. A primer on the NYC General Assembly website, the structural expression of the Occupy movement, explains, “Consensus is a creative thinking process: When we vote, we decide between two alternatives. With consensus, we take an issue, hear the range of enthusiasm, ideas and concerns about it, and synthesize a proposal that best serves everybody’s vision.”
Proponents make broad claims for consensus process. They argue that it is intrinsically more democratic than other methods, and that it fosters radical transformation, both within movements and in their relations with the wider world. As described in the action handbook of an Earth Day 1990 action to shut down Wall Street, which included a blockade of the entrances to the Stock Exchange and led to some two hundred arrests, “Consensus at its best offers a cooperative model of reaching group unity, an essential step in creating a culture that values cooperation over competition.”
Few, though, know the origins of the process, which shed an interesting and surprising light on its troubled real-world workings. Consensus decision-making first entered the world of grassroots activism in the summer of 1976, when a group of activists calling themselves the Clamshell Alliance began a direct-action campaign against the planned Seabrook Nuclear Plant.
Many activists of the time were well aware of what feminist writer Jo Freeman famously called “the tyranny of structurelessness.” The tendency in some early 1970s movements to abandon all structure in the name of spontaneity and informality had proven to be not just unworkable but undemocratic. Decisions still happened, but without an agreed-upon process — there was no accountability.
The organizers of “the Clam,” as it was often called, were eager to find a process that could prevent the pitfalls of structurelessness, without resorting to hierarchy. Two staffpeople from the American Friends Service Committee (AFSC), the longstanding and widely admired peace and justice organization affiliated with the Society of Friends, or Quakers, suggested consensus.
By this, they did not mean an informal process of building broad internal agreement of the sort used, for instance, by the pathbreaking civil rights group SNCC (the Student Nonviolent Coordinating Committee) in the early 1960s. The consensus process adopted by the Clam was much more formal, and grew directly out of Quaker religious practice.
As historian A. Paul Hare explains:

For over 300 years the members of the Society of Friends (Quakers) have been making group decisions without voting. Their method is to find a ‘sense of the meeting’ which represents a consensus of those involved. Ideally this consensus is not simply ‘unanimity,’ or an opinion on which all members happen to agree, but a ‘unity’: a higher truth which grows from the consideration of divergent opinions and unites them all.