The fight for 15 movement scored its biggest victory yet in April when California lawmakers agreed to raise the state’s minimum wage to $15 an hour by 2022. That follows a series of recent increases in U.S. states and cities—many of which passed via referendum, including in red states whose GOP representatives and senators oppose mandatory wage minimums. With Congress firmly under Republican control, a federal increase is unlikely to come soon, but the campaign’s piecemeal progress is gaining momentum.