The U.S. labor movement suffered a painful loss late Friday when workers at a Nissan factory in Mississippi overwhelmingly voted against joining the United Auto Workers union.

The election involving about 3,700 workers at the Canton manufacturing facility was the most closely watched of its kind in years. Desperate to expand its footprint in a region that can be hostile to unions, the UAW poured a decade of organizing into the Mississippi campaign, marrying a message of worker rights with civil rights to persuade the mostly African American workforce to join their ranks.

According to a preliminary count of ballots released by Nissan, the workers ultimately rejected that message, 2,244 to 1,307. Those results havent yet been certified by the National Labor Relations Board.

Earlier Friday evening, the UAW filed charges with the NLRB accusing Nissan of violating labor law during the election, The Associated Press reported. If the board agrees with the union that Nissan illegally swayed the vote, it can order a do-over election.

The UAW has tried for years to unionize the foreign transplant automakers that have settled in the American South, where wages are lower and unions weaker than in the Detroit area. The Nissan election provided the union with a shot at redemption after its stinging election loss at the Volkswagen plant in Chattanooga, Tennessee, in 2014. Union density is extremely low in Mississippi, with just 6.6 percent of workers belonging to a trade group, well below the national average.

Knowing a win in Canton would provide organized labor with a much-needed breakthrough, pro- and anti-union camps both poured heavy resources into trying to persuade workers who remained on the fence. Nissan held group meetings at the plant, with managers unsubtly warning workers that unionization would hurt them. The labor boards general counsel has accused the company of violating federal law by threatening layoffs if workers joined the UAW.

The union, meanwhile, brought in staff from around the country and enlisted fellow labor groups in its get-out-the-vote effort. Major progressive politicians weighed in on the unions behalf, with Sen. Bernie Sanders (I-Vt.) and Democratic National Committee Chairman Tom Perez penning op-ed pieces slamming Nissan for its anti-union tactics in the days before the vote. This could go down as one of the most vicious, and illegal, anti-union crusades in decades, Sanders wrote.

HuffPost reported on the companys tactics this week. Workers were taken off the factory floor and into roundtable meetings with managers. Videos ran on loop in the plant, painting unions in a bad light. One worker described the atmosphere as one of fear and intimidation. The facilitys human resources director told HuffPost that the company was merely trying to offer its viewpoint, highlighting a history of layoffs and strikes at union plants.

Nissan wasnt alone trying to sink the UAW. The states Republican governor, Phil Bryant, spoke out against the union days before the vote. On Facebook, Bryant said he hoped Nissan employees understand what the union will do to your factory in town, posting a photo apparently depicting rotting buildings in Detroit.

Vote no signs popped up on lawns and in the windows of area businesses, and Nissan hit the local airwaves with radio and television ads against the union.

Scott Waller, president of Mississippi Economic Council, a state business lobby, told HuffPost that he believed the UAW could jeopardize the Nissan plants success story. He said he also feared it would make Mississippi less appealing to the auto and auto parts manufacturers the state has spent years courting.

We have no way of knowing what the impact [would] be, Waller said of UAW representation. We just do honestly believe that this could have a very negative effect on Nissan Cantons ability to be competitive, and the states ability to be competitive.

The Nissan plant produces the Murano SUV and the Titan pickup truck. It opened in 2003, and has been one of the few sources of decent-paying blue-collar jobs in the area. Workers at the plant can make up to $26 per hour on the factory floor. While that may not be great money by Michigan manufacturing standards, it is a coveted job in the Canton area which Nissan was quick to remind workers in the days ahead of the vote.

The companys closing message to workers was a simple one : By unionizing, they could jeopardize what has been a godsend for Canton.

Pro-union workers countered that Nissan had not lived up to its promises, and they believed the UAW could raise working standards inside the plant. Wages have not risen at the pace many had been led to believe when the plant opened, while pensions had been frozen and health care costs increased.

Michael Carter, whos been at the plant since it opened, said the company portrayed his yes vote as turning your back on Nissan.

We understand, they provide a lot of jobs, Carter told HuffPost this week. But at the same time, you cant mistreat the people in there who are helping you make a profit. We gave Nissan every chance to change and they didnt.

Marvin Cooke, a paint technician, has friends who voted in favor of the union, but he voted against it. He said there wasnt much the UAW could offer that he didnt already have, and believed having a union would make the plant more likely to lay people off or close.

Were one of the highest paid [jobs] in the state, and you dont even have to have a high school degree, said Cooke, whos been at the plant for 14 years. I make more than some people do who have a doctoral degree.