The Workforce Consequences of Ending Mandatory Union Fees: Evidence from Janus v. AFSCME

Public-sector unions shape how state and local governments staff and size their workforces, yet clean shocks to union power are rare. The 2018 ruling by the U.S. Supreme Court in Janus v. AFSCME provided one, eliminating mandatory agency fees in the 21 states that had previously permitted them. I use a difference-in-differences design comparing affected states with right-to-work states and draw on two complementary datasets: three waves of the Census of Governments (CoG) and a balanced 2011–2025 annual panel that combines the CoG with the Annual Survey of Public Employment and Payroll. I find that Janus reduced part-time employment by 6.2 to 8.4 percent while leaving full-time employment unchanged, thereby raising the full-time share of the workforce by 1.13 to 1.75 percentage points. A simple model rationalizes this pattern: because union power sustained the part-time periphery, weakening it shifts the adjustment onto the least-protected positions rather than the full-time core. Per-worker earnings are unchanged for full-time and part-time workers alike, in both datasets. I additionally confirm the earnings null using individual-level CPS and state-level QCEW data.