US union membership posts largest gain since 2008, driven by pro-bargaining states

US union membership rose by 411,000 in 2025, the largest annual increase since 2008, reversing a long-term decline. Gains were concentrated in states with collective bargaining protections, highlighting the impact of 'right-to-work' laws. The uptick coincides with high public approval of unions, but the sustainability of this trend remains uncertain.