Until the beginning of 2004, Jimbo Wales dealt with all serious disputes other than simple vandalism (straightforward vandals could be blocked by any administrator). He was also the only person with the authority to ban users. In December 2003 he delegated that role in dispute handling to an Arbitration Committee, with initial membership of volunteer experienced users. Wales wrote in January 2004:
The Arbitration Committee [...] can impose a solution that I'll consider to be binding, with of course the exception that I reserve the right of executive clemency and indeed even to dissolve the whole thing if it turns out to be a disaster. But I regard that as unlikely, and I plan to do it about as often as the Queen of England dissolves Parliament against their wishes, i.e., basically never, but it is one last safety valve for our values.
In April 2007, Wales confirmed that the Committee could overturn any decision he makes in his traditional capacity within Wikipedia.
The original Arbitration Committee was appointed in 2004 by Jimbo Wales, primarily chosen from people who volunteered to help with the mediation and arbitration processes. Since then, arbitrators have been appointed based on the results of annual advisory elections. In the past, Jimbo did not considered himself bound by the results of the elections and has stated that he will not appoint candidates with less than 50% support. Nevertheless, he generally appointed arbitrators from among the candidates with the highest percentages of positive votes. Historically, users with past experience were sometimes re-appointed for continuity, and vacancies arising from mid-term resignations were sometimes filled by extending the terms of other sitting arbitrators.
The committee initially comprised twelve arbitrators who served terms from one to three years, in three "tranches", so that about a third of the committee was up for reappointment each year. After the 2008 election, Jimbo increased the size of the committee to eighteen. From the 2009 elections onwards, the maximum term was reduced to two years, with two instead of three tranches. In the 2011 elections, the size of the Committee was reduced to a maximum of fifteen members. In 2018 this was reduced to 13.
While Jimbo still holds reserve powers over the committee, the established community election process now selects committee members directly.