American Federation of Labor in the context of "American Left"

The Boston police strike occurred on September 9, 1919, when Boston police officers went on strike seeking recognition for their trade union and improvements in wages and working conditions. Police Commissioner Edwin Upton Curtis denied that police officers had any right to form a union, much less one affiliated with a larger organization like the American Federation of Labor (AFL), which some attribute to concerns that unionized police would not protect the interest of city officials and business leaders. Attempts at reconciliation between the Commissioner and the police officers, particularly on the part of Boston's mayor, Andrew James Peters, failed.

During the strike, Boston experienced several nights of lawlessness. Several thousand members of the Massachusetts State Guard, supported by volunteers, restored order by force. Press reaction both locally and nationally described the strike as Bolshevik-inspired and directed at the destruction of civil society. The strikers were called "deserters" and "agents of Lenin". Samuel Gompers of the AFL recognized that the strike was damaging the cause of labor in the public mind and advised the strikers to return to work. Commissioner Curtis refused to re-hire the striking policemen. He was supported by Massachusetts governor Calvin Coolidge, whose rebuke of Gompers earned him a national reputation.

The American Federation of Labor and Congress of Industrial Organizations (AFL-CIO) is a national trade union center that is the largest federation of unions in the United States. It is made up of 61 national and international unions, together representing nearly 15 million active and retired workers. The AFL-CIO engages in substantial political spending and activism, typically in support of progressive and pro-labor policies.

The AFL-CIO was formed in 1955 when the American Federation of Labor and the Congress of Industrial Organizations merged after a long estrangement. Union membership in the US peaked in 1979, when the AFL-CIO's affiliated unions had nearly twenty million members. From 1955 until 2005, the AFL-CIO's member unions represented nearly all unionized workers in the United States. Several large unions split away from AFL-CIO and formed the rival Change to Win Federation in 2005, although a number of those unions have since re-affiliated, and many locals of Change to Win are either part of or work with their local central labor councils. The largest unions currently in the AFL-CIO are the Service Employees International Union (SEIU), with 2 million members, American Federation of Teachers (AFT) with approximately 1.7 million members, American Federation of State, County and Municipal Employees (AFSCME), with approximately 1.4 million members, and United Food and Commercial Workers with 1.2 million members.

International Workers' Day, also called Labour Day in some countries and often referred to as May Day, is a celebration of labourers and the working classes that is promoted by the international labour movement and occurs every year on 1 May, or the first Monday in May.

Traditionally, 1 May is the date of the European spring festival of May Day. The International Workers Congress held in Paris in 1889 established the Second International for labor, socialist, and Marxist parties. It adopted a resolution for a "great international demonstration" in support of working-class demands for the eight-hour day. The date was chosen by the American Federation of Labor to commemorate a general strike in the United States, which had begun on 1 May 1886 and culminated in the Haymarket affair on 4 May. The demonstration subsequently became a yearly event. The 1904 Sixth Conference of the Second International, called on "all Social Democratic Party organisations and trade unions of all countries to demonstrate energetically on the First of May for the legal establishment of the eight-hour day, for the class demands of the proletariat, and for universal peace".

The Knights of Labor (K of L), officially the Noble and Holy Order of the Knights of Labor, was the largest American labor movement of the 19th century, claiming for a time nearly one million members. It operated in the United States as well in Canada, and had chapters also in Great Britain and Australia. Terence V. Powderly was one of the most notable leaders of the organization as he was the leader during its rapid rise and decline. The Knights of Labor promoted the social and cultural uplift of the worker, and demanded the eight-hour day. In some cases it acted as a labor union, negotiating with employers, but it was never well organized or funded. It was notable in its ambition to organize across lines of gender and race and in the inclusion of both skilled and unskilled labor. It grouped all workers, regardless of occupation, into a single body. After a rapid expansion in the mid-1880s, it suddenly lost its new members and succumbed to a jurisdictional battle with the new American Federation of Labor. The Knights of Labor had served as the first mass organization of the working class in the United States.

Founded by Uriah Stephens on December 28, 1869, the Knights of Labor reached 28,000 members in 1880, and 100,000 in 1884. By 1886, it had nearly 800,000 members: 20% of all workers. Its frail organizational structure could not cope as charges of failure, violence, allegations, and backlash following the 1886 Haymarket Square riot battered it. Most members abandoned the movement in 1886–1887, leaving at most 100,000 members in 1890. Many opted to join groups that helped to identify their specific needs instead of the KOL which addressed many different types of issues. The Panic of 1893, the largest economic depression in US history at the time, ended the Knights of Labor's importance. While their national headquarters closed in 1917, remnants of the Knights of Labor survived until 1949, when the group's last 50-member local dropped its affiliation.