Bernd Osterloh, who is the Volkswagen AG General and Group Works Council chairman, said that future investments in the South might be hurt if workers will not unionize, according to Reuters.
The comments come days after Volkswagen Chattanooga workers voted against representation by the United Auto Workers Union.
After years of quiet work by union leaders and a contentious campaigning period, officials announced Friday night that Volkswagen employees opted against UAW representation with a 712-626 vote.
But at that announcement, Volkswagen Chattanooga President Frank Fischer said the vote wasn't against the works council and that there is still support for that idea.
Osterloh said that, if co-determination isn't guaranteed, it would be more difficult to vote in favor of building another auto plant in the South.
"I can imagine fairly well that another VW factory in the United States, provided that one more should still be set up there, does not necessarily have to be assigned to the South again," Osterloh said, according to Reuters.
The works council is a 20-member group that has an even division of labor and management representatives. They have to approve decisions about where to locate new plants.
Osterloh's comments have been the target of criticism in the past.
In the fall, Osterloh said that having a works council is important to producing a second vehicle in Chattanooga.
"We know how important that vehicle is for Chattanooga," Osterloh said, according to Reuters.
With help from the National Right to Work Legal Foundation, some VW employees filed charges with the National Labor Relations Board against Volkswagen America, in part because of that statement.
Some workers and lawyers thought the comments constituted coercion.
NLRB officials have since recommended dismissal of those charges, but not because his statement didn't qualify as coercive. Instead, the NLRB decision said that Osterloh isn't bound by U.S. law because he's in Germany.
Some Volkswagen AG leaders, such as Osterloh, want Chattanooga’s plant to be a part of its works council system. It’s currently one of the only plants out of about 100 around the world that operates outside that system.
Because the National Labor Relations Act forbids companies to have an internal union, organizing the local plant can’t be done exactly like the German model.
Volkswagen AG leaders want a works council because it would allow them to stay in touch with ideas and thoughts from Chattanooga workers and come to future deals about working conditions, Horst Neumann, VW's board member for human resources, said, according to Automotive News.
In his most recent comments, Osterloh said that conservatives might be to blame for anti-union feelings.
Sen. Bob Corker and other Republicans campaigned against the UAW efforts, saying that it would hurt the state's ability to attract auto suppliers. They argued that the UAW has a bad reputation, in part because of its ties to the Detroit auto industry.
"The conservatives stirred up massive, anti-union sentiments," Osterloh said, according to Reuters. "It's possible that the conclusion will be drawn that this interference amounted to unfair labor praxis."
Despite last week's vote against UAW representation, some Volkswagen leaders still want Chattanooga workers to be part of the Global Works Council.
But it's still unclear exactly how that would work.
And Gunnar Kilian, secretary-general of VW's works council, told Reuters and The New York Times that he plans to come to the United States within the next two weeks to consult labor law experts and figure out the next steps toward reaching his goal.
Meanwhile, state and local leaders are in talks with VW in hopes of getting a new vehicle made in Chattanooga.
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Updated @ 1:14 p.m. on 2/19/14 to make a clarification.