(Reuters) – Workers at a Chinese-owned auto glass plant in southwestern Ohio will finish voting on Thursday on whether to join the United Auto Workers, in a test of the union’s strategy for organizing foreign-owned auto factories after a stinging loss in the U.S. Deep South in August.

The vote, which began on Wednesday, involves roughly 1,500 workers at the Fuyao Glass Industry Group Co Ltd plant in Moraine, a Dayton suburb that was once home to a large, unionized General Motors Co assembly plant.

The UAW needs a win after losing a bitterly contested vote at a Nissan Motor Co Ltd plant in Mississippi in August, which extended a decades-long record of failure to organize a major automaker’s plant in the U.S. South.

The vote also comes amid an expanding U.S. Justice Department probe into alleged misuse of funds at UAW training centers funded by the Detroit automakers.

Fuyao, a Chinese automotive glass supplier whose global customers include General Motors Co, Ford Motor Co, Fiat Chrysler Automobiles NV, Daimler AG and Toyota Motor Corp, opened the plant in Moraine in 2016 as part of a broader $1 billion expansion in the United States.

Though UAW membership has crept up since the end of the Great Recession, it is around half of what it was in 1998 and well below a peak of 1.5 million members in 1979. The Detroit automakers and their suppliers have slashed workforces at UAW-represented factories over the past 30 years as they have automated and lost sales to European and Asian rivals.

This year could be the first in which North American vehicle production by the unionized Detroit Three automakers falls to less than half of total vehicle output in the region, according to IHS Markit.

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At Fuyao’s Ohio factory, the UAW has told workers it can help them secure better safety and higher pay.

Rich Rankin, head of the UAW region covering Ohio and Indiana, said workers at the Fuyao plant start at $10 an hour, much less than the $22 an hour they can make at two other unionized automotive glass plants in his region.

He said he grew up hearing about U.S. companies that would go abroad and pay workers low wages in poor conditions.

“It’s amazing to me that this is now happening to U.S. workers in America’s manufacturing heartland,” he said on Tuesday.

The battle over unionizing at what was once a union-represented GM plant in a state with nearly 50,000 active UAW members has brought in politicians on both sides.

U.S. Senator Sherrod Brown, a Democrat, wrote to Fuyao in October saying its success is “contingent on creating a safe and supportive working environment.”

Meanwhile, 15 Ohio Republican state representatives wrote an open letter urging employees to reject “outside forces” trying to come into the Chinese supplier’s Ohio factory.

Harley Shaiken, a professor at the University of California, Berkeley, specializing in labor and the global economy, said on Wednesday that Ohio’s history of unionization might be one of the few factors working in the UAW’s favor.

But Shaiken said that rules preventing unions from talking to workers inside factories meant that employers have “vast resources and leverage to create an atmosphere of fear” for workers ahead of unionizing votes.

“It’s not a level playing field, as the unions aren’t even allowed in the stadium,” Shaiken added.