70%Decline in union membership rate (1954–2024)
5-6%Increase in income inequality per 1% union membership drop
$13,000Annual union wage premium for union vs non-union workers
10.1%Current US union membership rate (2023)
Unions are groups of workers who negotiate together. When many workers are in unions, companies can't easily cut wages — because everyone stands together. But unions have shrunk from covering 1 in 3 workers to just 1 in 10. As unions got weaker, wages for regular workers stopped growing, CEOs started earning hundreds of times more, and inequality soared.
Union decline is both a cause and consequence of inequality. The causal mechanism: unions set wage floors and norms that affect non-union workers too ("spillover effect"). When 35% of workers were unionized, even non-union employers had to match wages to compete for labor. At 10%, this effect disappears. BLS data shows union workers earn $13,000/year more on average than comparable non-union workers. The Taft-Hartley Act (1947), right-to-work laws (now 27 states), PATCO firings (Reagan 1981), and offshoring accelerated decline.
Western & Rosenfeld (2011) ASR: union decline explains 1/3 of the rise in male wage inequality 1973-2007. Card, Lemieux & Riddell (2004) JOLE: union wage premium after controlling for observable characteristics: 10-20%. EPI analysis (2024): states with higher union density have lower Gini coefficients (r=-0.61). Spillover effect: Rosenfeld & Kleykamp (2012) show 60% of union membership's effect on wages operates through norms transmission to non-union sector. Public sector unions (34.4% density) provide floor; private sector (6.0%) near historic low. 2023 UAW wins: 25% wage increase — first significant private sector union victory in years.
BLS Union Membership data: bls.gov/news.release/union2.htm (annual, January release). Historical data: bls.gov/opub/mlr/2019/article/union-membership-rate. EPI union data: epi.org/data/#?subject=unionization. Western & Rosenfeld (2011) ASR 76(4):513-537. Card et al. (2004) JOLE 22(S1). UAW contract 2023: uaw.org. Right-to-work law map: nlrb.gov. NLRB election data: nlrb.gov/resources/statistics. State Gini coefficient: ACS 2022.
The Wage Floor Collapse
As union membership fell, the wage floor disappeared. The rich got much richer. Workers' wages flatlined in real terms. This is not coincidence.
Union Membership Rate vs Income Inequality (Gini) — 1950–2024
As union membership falls, inequality rises — the mirror image relationship
Union Wage Premium by Industry (2023)
How much more union workers earn than non-union in same sector
Union Membership by Sector (2023)
Where unions have survived — and where they've collapsed
The Spillover Effect Is Real
Unions don't just benefit members. When 35% of workers were unionized, non-union employers had to match wages to attract workers. The entire wage floor rose. Now that only 6% of private sector workers are unionized, that floor has largely disappeared. The 2023 UAW strike won 25% wage increases — and within months, non-union automakers announced raises to compete. The mechanism still works. There just aren't enough unions left to use it.
Sources
BLS Union Membership Annual Report (2024) · EPI State of Working America Data (2024) · Western & Rosenfeld, American Sociological Review (2011) · Card, Lemieux & Riddell, JOLE (2004) · NLRB Election Data (2024)