WASHINGTON, March 18 (Reuters) - Workers at Volkswagen's

Chattanooga, Tennessee, assembly plant are seeking

an election to join the United Auto Workers union, setting up a

critical test for UAW President Shawn Fain's unprecedented

campaign to expand the union's reach to foreign-owned automakers

in the southern United States.

The UAW said a supermajority of eligible workers at the VW

plant have signed union cards in about three months. The workers

have filed a petition with the National Labor Relations Board

(NLRB) seeking a vote to join the union. It would be the third

time in 10 years that the UAW has sought to represent VW

Chattanooga workers.

For more than two decades, the UAW has tried and failed to

organize non-union U.S. auto assembly plants established by

Asian and European automakers, mostly in southern states with

laws and political leaders that are hostile to unions. The UAW

has not organized workers at Tesla or other electric

vehicle startups such as Rivian.

Winning a vote to organize the VW plant would be a

significant milestone for the UAW in an election year where both

U.S. President Joe Biden and his presumptive Republican rival

Donald Trump are aggressively courting votes from UAW members in

Michigan and other industrial swing states.

Biden, in a statement released by the White House,

congratulated the workers and noted that many VW plants

internationally were unionized. "As the most pro-union president

in American history, I believe American workers, too, should

have a voice at work. The decision whether to join a union

belongs to the workers," Biden said.

After winning record new contracts with the Detroit Three

automakers last fall, Fain launched a first-of-its-kind campaign

to organize the entire nonunion auto assembly sector in the

U.S., initiating simultaneous organizing efforts at non-union

operations owned by Toyota ( TM ), Mercedes, Hyundai and other

automakers.

VW, which produces the Atlas and ID.4 at the plant, said

Monday it "will fully support an NLRB vote so every team member

has a chance to vote in privacy in this important decision. The

election timeline will be determined by the NLRB."

The NLRB said it had received the union election petition

for 4,300 employees at the VW plant to be represented by the

UAW. If both sides do not agree on the election details, the

NLRB will hold a pre-election hearing on March 26 in Atlanta.

Two attempts to organize VW's plant in Chattanooga narrowly

failed. In 2019, VW workers at the plant rejected union

representation in an 833-776 vote. Earlier efforts to organize

Nissan Motor ( NSANF ) plants in Mississippi and Tennessee also

failed by wide margins.

The UAW in November announced campaigns at 13 nonunion

automakers, including at Tesla, Toyota Motor ( TM ),

Hyundai, Rivian, BMW and Mercedes-Benz. Senators in

January pressed the automakers to remain neutral during

organizing.

Earlier this month, the UAW said that more than 30% of

workers at a Toyota ( TM ) factory in Missouri are seeking to join the

union.

The UAW said last month a majority of hourly workers at a

Mercedes Benz Alabama factory have signed union authorization

cards.

VW said in November it would hike pay for Tennessee factory

workers by 11%, joining several foreign automakers who have

announced significant pay and other compensation improvements in

response to the UAW contract.