As recently as late May, Choi Seung-ho was hailed as a hero. Rallying workers at Samsung Electronics?to demand a greater share of profits, the union leader secured a staggering windfall, particularly for some semiconductor workers who were promised bonuses of roughly $400,000 this year.

The celebration was short-lived. Workers in less lucrative sections were furious over their much smaller bonuses, in some cases a mere 1% of what their memory-chip colleagues won. Some began showing up to work in black clothes and masks to signal their discontent.

“It’s too bad that the outcome left some people unhappy,” Choi said in a recent interview, days before he put his leadership to a vote of confidence. He kept his job, with 88% of union members voting last week to support him, but only after the departure of thousands. He’s now left commanding a highly fractured organization: his union’s latest membership, at under 55,000, has fallen to less than half of Samsung’s domestic workforce, meaning it’s lost its power to be the single negotiating channel with management.