NASHVILLE (AP) - Nearly 20 months after narrowly losing a union election at Volkswagen's lone U.S. plant in Tennessee, the United Auto Workers are up for another vote affecting a much smaller number of employees.

The two-day vote scheduled to begin Thursday at the German automaker's Chattanooga factory is about whether a unit of 165 skilled-trades workers want to have the UAW negotiate collective bargaining agreements on their behalf.

Volkswagen isn't happy about the union seeking to represent the smaller group of workers, but the election is expected to proceed even as the company pursues an appeal to the National Labor Relations Board.

A UAW success at the plant would break a long losing streak among foreign-owned automakers in the South. That's a prospect welcomed by labor supporters and dreaded by anti-union politicians in the region.

Some things to know about the union vote at Volkswagen:

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A QUESTION OF TIMING

Volkswagen has been reeling since the company admitted that 482,000 diesel vehicles in the U.S. contained software to cheat pollution measurements on government tests. Those revelations led Volkswagen's CEO to resign and the company to announce cost-cutting measures to cope with the crisis.

Volkswagen has publicly reaffirmed its plans to build a new SUV at the plant next year, and the U.S. will remain a key market. But November sales were down almost 25 percent from a year ago, and Chattanooga-made Passats plummeted by 60 percent despite the release of an updated version of the midsized sedan.

Republican Gov. Bill Haslam has chided the union for petitioning for another vote amid all the turmoil facing the company. The UAW responded that it can play a key role in Volkswagen's resurgence.

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THE GLOVES ARE OFF WITH VOLKSWAGEN

The strong labor influence at Volkswagen in Germany has long been a source of irritation for Tennessee Republicans keen on keeping the union out of the Chattanooga plant. But in this election, Volkswagen is leading the charge against the unionization effort.

Unlike in the runup to the 2014 vote, the union and the company have not signed a pre-election agreement. Volkswagen argues that allowing the small group of machinists and electricians to form their own bargaining unit runs contrary to the company's hopes of creating a German-style works council to represent both hourly and salaried employees at the plant.

Especially galling to the UAW has been Volkswagen's decision to hire a law firm that touts its specialization in "strategies for lawful union avoidance." The union says that move is at odds with Volkswagen's core principles of co-determination between workers and management.

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MICRO VERSUS WALL-TO-WALL

Volkswagen insists that the only proper bargaining unit at the plant would include all 1,408 hourly employees working one factory floor, regardless of whether they work in production or maintenance.

The regional director of the National Labor Relations Board ruled that the maintenance workers, who make up about 12 percent of the hourly workforce, "share a community of interest" over a variety of job-specific issues such as skills and training requirements, wages, hours and uniforms.

The decision relied on previous NLRB rulings in favor of "micro units" comprising certified nursing assistants at an Alabama rehabilitation center and fragrance and cosmetics sales staff at a Macy's department store in Massachusetts. In both of those cases the federal panel rejected the employer's insistence on "wall-to-wall" labor votes.

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GETTING IN THE DOOR

The union is expressing confidence that it has the numbers to prevail in this week's vote and the legal precedents to turn back the company's challenge to the National Labor Relations Board's decision. But the UAW won't be happy until it has gained exclusive bargaining rights for all hourly workers at the plant.

"We had to move the needle somehow," said Gary Casteel, the UAW's secretary-treasurer. "So this is just a first step in that direction."

Other foreign automakers that have kept the UAW at bay - Mercedes-Benz in Alabama, BMW in South Carolina and Nissan in Tennessee and Mississippi - will be keeping close watch.