The founding of Solidarity was an unprecedented event not only in Poland, ruled by a one-party Communist regime, but also in the whole Eastern bloc. It meant a break in the hard-line stance of the Party which in another protest in 1970 had ended in bloodshed with dozens of people killed by machine gun fire and over 1,000 injured.
Two factors contributed to the initial success of the unions: it was backed by a group of intellectual dissidents (KOR) and it was based on the rules of non-violence.
The ideas of the Solidarity movement spread like wildfire throughout Poland; more and more new unions were formed and joined the federation. The program, although concerned with trade union matters, was universally regarded as the first step towards dismantling the Party monopoly.
"The Rural Solidarity", a union of farmers, was created in May 1981. By the end of 1981, Solidarity had nine million members. Using strikes and other industrial action, the union sought to block government initiatives. On December 13, 1981, the government leader Wojciech Jaruzelski started a crack-down on Solidarity, declaring martial law, suspending the union, and temporarily imprisoning most of its leaders. Poland then banned Solidarity on October 8, 1982. Martial Law was formally lifted in July, 1983, though many heightened controls on civil liberties and political life, as well as food rationing, remained in place through the mid- to late 1980s.
Throughout the mid-1980s, Solidarity persisted solely as an underground organization, supported by the Church and the CIA. But by the late 1980s, Solidarity was sufficiently strong to frustrate Jaruzelski's attempts at reform, and nationwide strikes in 1988 forced the government to open a dialogue with Solidarity.
In April 1989, Solidarity was legalised and allowed to participate in the upcoming elections. In these limited elections union candidates won a striking victory. By the end of August a Solidarity-led coalition government was formed and in December Walesa was elected president, resigning from his post in Solidarity.
Since then, the organisation has become a more traditional trade union, but a political arm was founded in 1996 as Solidarity Electoral Action (now having a negligible political significance). Solidarity currently has around 1.5 million members.
From the beginning, Solidarity was an avowedly pluralist organization that included traditional Trotskyists, left-wing Shachtmanites, and Luxemburgists. Founded on the basis of far-left regrouping, Solidarity sought to unite with other groups and create a large revolutionary-socialist and feminist party. Calling for a mass Labor Party, Solidarity also had substantial impact in the trade union movement, especially in Teamsters for a Democratic Union (TDU). It has also had great success in circulating thousands of copies of its journal, Against the Current.
During the 1990s, Solidarity has had two organizations merge with it—the Forth Internationalist Tendency (a group expelled from the SWP) in September 1992 and Activists for Independent Socialist Politics (a Socialist Action split that had previously worked in Committees of Correspondence). It has also initiated internal fractions that work inside the Labor Party and the Green Party.
In 2000, Solidarity endorsed both the Green Party's Ralph Nader and the Socialist Party's David McReynolds for President. Recently, discussions of "Left Refoundation" have also been initiated between Solidarity and groups such as Left Turn, Freedom Road Socialist Organization, and Detroit's Trotskyist League. Further, many members of the organization are also interested in stronger relations (if not a merger) with the Socialist Party USA.