WASHINGTON – A contentious labor dispute between the government and Boeing Co. that spawned a national political fight likely will be settled after the company and the Machinists union announced Wednesday they'd reached a tentative deal on a new four-year collective bargaining agreement.

If the deal is finalized, it would appear to leave in place the work at a new $750 million Boeing plant in South Carolina, a right-to-work state where the company opened a new production line for its 787 airplane.

The National Labor Relations Board filed a lawsuit earlier this year alleging that Boeing violated labor laws by opening the South Carolina line. Acting on a complaint from the union, the agency claimed that Boeing was punishing Washington state workers for past strikes and said the company should return the work to Washington.

Boeing has vigorously denied the charges, claiming it opened the South Carolina plant for valid economic reasons.

The new agreement guarantees that a different aircraft -- the 737 Max -- would be assembled at union facilities in Renton, Wash., said Tom Wroblewski, president of Machinists Union District 751.

Wroblewski said that if union members vote to approve the deal in the coming weeks, the union would inform the NLRB that it has no further grievances with Boeing...