Labor unions represent United States workers in many industries recognized under US labor law since the 1935 enactment of the National Labor Relations Act. Their activity centers on collective bargaining over wages, benefits, and working conditions for their membership, and on representing their members in disputes with management over violations of contract provisions. Larger labor unions also typically engage in lobbying activities and electioneering at the state and federal level.
Most unions in the United States are aligned with one of two larger umbrella organizations: the AFL-CIO created in 1955, and the Change to Win Federation (Strategic Organizing Center or SOC) which split from the American Federation of Labor-Congress of Industrial Organizations (AFL–CIO) in 2005. Both advocate policies and legislation on behalf of workers in the United States and Canada, and take an active role in politics. The AFL–CIO is especially concerned with global trade issues.
In 2025, 14.7 million U.S. wage and salary workers were union members, representing 10.0 percent of wage and salary workers. In 1983, the first year with comparable data, the membership rate was 20.1 percent and 17.7 million workers were union members. The 2025 membership rate was 32.9 percent in the public sector and 5.9 percent in the private sector. Because the October 2025 Current Population Survey was not collected during the federal government shutdown, the 2025 annual estimates use 11 monthly observations and are not strictly comparable with annual averages for other years. From a global perspective, in 2016 the US had the fifth lowest labor union density of the 36 OECD member nations.See: Trade Union Density. OECD. StatExtracts. Retrieved: January 1, 2017.See also Trade union#Prevalence worldwide
In the 21st century, the most prominent unions are among public sector employees such as city employees, government workers, teachers and police. Members of unions are disproportionately older, male, and residents of the Northeast, the Midwest, and California.Not With a Bang, But a Whimper: The Long, Slow Death Spiral of America's Labor Movement, Richard Yeselson, The New Republic, June 6, 2012 There is a substantial wage gap between union and nonunion workers in the U.S.; unionized workers average higher pay than comparable nonunion workers (when controlling for individual, job, and labor market characteristics); research shows that the union wage gaps are higher in the private sector than in the public sector, and higher for men than women.David A. MacPherson & Barry T. Hirsch, https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3855962 Five Decades of Union Wages, Nonunion Wages, and Union Wage Gaps at Unionstats.Com], IZA Institute of Labor Economics, IZA Discussion Paper No. 14398 (2021). Private-sector union strength positively affects the wages of nonunion private-sector wages" (when controlling for background conditions, such as industry, the automation risk, offshoring, public-sector union strength, overall employment levels, and other factors); this is called the union spillover effect.Patrick Denice & Jake Rosenfeld, Unions and Nonunion Pay in the United States, 1977–2015, Sociological Science (2018).
Although much smaller compared to their peak membership in the 1950s, American unions remain a political factor, both through mobilization of their own memberships and through coalitions with like-minded activist organizations around issues such as immigrant rights, environmental protections, trade policy, health care, and living wage campaigns. Of special concern are efforts by cities and states to reduce the pension obligations owed to unionized workers who retire in the future. A study of U.S. elections from 1964 to 2004 found that unions increase voter turnout of both members and nonmembers.Jan E. Leighley & Jonathan Nagler, Unions, Voter Turnout, and Class Bias in the U.S. Electorate, 1964–2004, Journal of Politics, Vol 69, Issue 2 (2007), pp. 430-441. Labor unions have a longstanding alliance with the Democratic Party, and union members make up an important part of the party's base.Taylor E. Dark, The Unions and the Democrats: An Enduring Alliance (Cornell University Press, 2018). By contrast, the Republican Party has opposed unions and championed various anti-union policies, such as the adoption of right-to-work laws, restrictions on public-sector union collective bargaining, the repeal of prevailing wage laws, and preemption of local minimum wage laws.Ruth Milkman & Stephanie Luce, Labor Unions and the Great Recession, RSF: The Russell Sage Foundation Journal of the Social Sciences (2017), Vol. 3, Issue 3, pp. 145-165: "In the private sector, the U.S. political and regulatory context became increasingly unfavorable to unionism starting in the 1970s, but that was far less often true in the public sector until very recently. However, in the twenty-first century, and especially since the Great Recession, concerted political attacks on public sector unionism have spread, and anti-unionism has become a cornerstone of conservative ideology."Laura C. Bucci & Joshua M. Jansa, Who passes restrictive labour policy? A view from the states, Journal of Public Policy (2021), Vol. 41, Issue 3, pp. 409-49.
There is substantial evidence that labor unions reduce economic inequality. Research suggests that rising income inequality in the United States is partially attributable to the decline of the labor movement and union membership,Doree Armstrong (February 12, 2014). Jake Rosenfeld explores the sharp decline of union membership, influence. UW Today. Retrieved December 19, 2014. See also: Jake Rosenfeld (2014) What Unions No Longer Do. Harvard University Press. Keith Naughton, Lynn Doan and Jeffrey Green (February 20, 2015). As the Rich Get Richer, Unions Are Poised for Comeback. Bloomberg. Retrieved February 20, 2015. "A 2011 study drew a link between the decline in union membership since 1973 and expanding wage disparity. Those trends have since continued, said Bruce Western, a professor of sociology at Harvard University who co-authored the study." and that this is not only a correlation.Michael Hiltzik (March 25, 2015). IMF agrees: Decline of union power has increased income inequality. Los Angeles Times. Retrieved March 26, 2015. "The IMF analysis suggests these trend lines aren't merely correlations, but the first is caused, at least partially, by the second. Indeed, the paper says that roughly half the increase in income inequality in advanced economies is 'driven by deunionization.'" Research has also found that unions can harm profitability, employment and business growth rates.Hirsch, Barry T. "What do unions do for economic performance?." Journal of Labor Research 25, no. 3 (2004): 415–455.Vedder, Richard, and Lowell Gallaway. "The economic effects of labor unions revisited." Journal of labor research 23, no. 1 (2002): 105-130.
History
Unions began forming in the mid-19th century in response to the social and economic impact of the Industrial Revolution. National labor unions began to form in the post-Civil War Era. The Knights of Labor emerged as a major force in the late 1880s, but it collapsed because of poor organization, lack of effective leadership, disagreement over goals, and strong opposition from employers and government forces.
The American Federation of Labor, founded in 1886 and led by Samuel Gompers until his death in 1924, proved much more durable. It arose as a loose coalition of various local unions. It helped coordinate and support strikes and eventually became a major player in national politics, usually on the side of the Democrats.
American labor unions benefited greatly from the New Deal policies of Franklin Delano Roosevelt in the 1930s. The Wagner Act, in particular, legally protected the right of unions to organize. Unions from this point developed increasingly closer ties to the Democratic Party, and were considered a backbone element of the New Deal Coalition.
Post-WWII
Pro-business conservatives gained control of Congress in 1946, and in 1947 passed the Taft–Hartley Act, drafted by Senator Robert A. Taft. President Truman vetoed it but the Conservative coalition overrode the veto. The veto override had considerable Democratic support, including 106 out of 177 Democrats in the House, and 20 out of 42 Democrats in the Senate.Benjamin C. Waterhouse, Lobbying in America, (Princeton University Press, 2013) 53. The law, which is still in effect, banned union contributions to political candidates, restricted the power of unions to call strikes that "threatened national security," and forced the expulsion of Communist union leaders (the Supreme Court found the anticommunist provision to be unconstitutional, and it is no longer in force). The unions campaigned vigorously for years to repeal the law but failed. During the late 1950s, the Landrum Griffin Act of 1959 passed in the wake of Congressional investigations of corruption and undemocratic internal politics in the Teamsters and other unions.
In 1955, the two largest labor organizations, the AFL and CIO, merged, ending a division of over 20 years. AFL President George Meany became President of the new AFL–CIO, and AFL Secretary-Treasurer William Schnitzler became AFL–CIO Secretary-Treasurer. The draft constitution was primarily written by AFL Vice President Matthew Woll and CIO General Counsel Arthur Goldberg, while the joint policy statements were written by Woll, CIO Secretary-Treasurer James Carey, CIO vice presidents David McDonald and Joseph Curran, Brotherhood of Railway Clerks President George Harrison, and Illinois AFL–CIO President Reuben Soderstrom.Soderstrom, Carl; Soderstrom, Robert; Stevens, Chris; Burt, Andrew (2018). Forty Gavels: The Life of Reuben Soderstrom and the Illinois AFL-CIO. 3. Peoria, IL: CWS Publishing. pp. 95–96.
The percentage of workers belonging to a union (or "density") in the United States peaked in 1954 at almost 35% and the total number of union members peaked in 1979 at an estimated 21.0 million. Membership has declined since, with private sector union membership beginning a steady decline that continues into the 2010s, but the membership of public sector unions grew steadily.
After 1960 public sector unions grew rapidly and secured good wages and high pensions for their members. While manufacturing and farming steadily declined, state- and local-government employment quadrupled from 4 million workers in 1950 to 12 million in 1976 and 16.6 million in 2009.U.S. Census Bureau, "Census Bureau Reports State and Local Government Employment Remains at 16.6 Million" (press release Aug. 10, 2010) Adding in the 3.7 million federal civilian employees, in 2010 8.4 million government workers were represented by unions,This includes some people who are covered by union contracts but are not themselves members. including 31% of federal workers, 35% of state workers and 46% of local workers.Bureau of Labor Statistics, "Table 3. Union affiliation of employed wage and salary workers by occupation and industry"