Correction: An earlier version of this article misstated the cost of a new Boeing manufacturing plant in South Carolina. The cost was $750 million, not $750 billion. This version has been corrected.

During nearly four decades at the National Labor Relations Board, Lafe Solomon was a mostly anonymous cog in the federal bureaucracy. But that all changed in April, when Solomon filed a complaint alleging that Boeing violated labor law by opening a new manufacturing plant for its 787 Dreamliner in South Carolina.

The case has made him a villain to business — as well as many workers who view his action as hurting an already weak economy. The complaint has been invoked by many Republicans and their allies as Exhibit A in what they see as the excesses of the Obama administration’s regulatory approach.

“You see [President Obama] stacked the National Labor Relations Board with anti-business cronies who want to dictate to a private company, Boeing, where they can build a plant. No president should kill jobs in South Carolina, or any other state for that matter, simply because they choose to go to a right-to-work state,” Texas Gov. Rick Perry said when he announced his candidacy for president in August.

Solomon is embroiled in a tussle with the House Oversight and Government Reform Committee, which has subpoenaed his Boeing case files. Solomon could face contempt charges if he continues to refuse to relinquish the files — something he says would undermine his legal strategy.

Through it all, Solomon has remained unbowed, even if he is surprised by the political ruckus that he has stirred up.

“We knew the case had national significance from the very beginning. We took it very seriously from that point of view,” Solomon said in an interview. But, he added, “I don’t think I could have possibly predicted that I would become part of the Republican platform for president.”

His work has also left Obama sounding a tad defensive. Asked about the Boeing case during a June news conference, Obama said companies must follow the law, but he quickly added: “What I think defies common sense would be a notion that we would be shutting down a plant or laying off workers because labor and management can’t come to a sensible agreement.”

Solomon said he wanted to settle the case and had no intention of seeing the South Carolina plant shut. But he said he saw no option other than to file the complaint.

“It was not my goal to do anything that would harm his presidency in any way,” Solomon said. “But I feel I had to do this. I took an oath of office to enforce the National Labor Relations Act.”

The NLRB is an independent agency established to safeguard employees’ rights to organize unions. The agency also polices unfair labor practices.

Since being named the board’s acting general counsel, Solomon has taken several other actions that have outraged business leaders and their political allies. He threatened to sue four states — South Carolina, Arizona, South Dakota and Utah — where voters ratified constitutional amendments that would prevent unions from organizing using signed authorization cards filled out by workers. The amendments contradict federal law.

He also supported a case against a Connecticut ambulance company, American Medical Response, for firing a worker who disparaged her boss on Facebook. Earlier this month, the board issued a report on employees’ use of social media, which generally protected employees’ right to vent about their jobs online.

In the Boeing case, the NLRB alleges that the giant aerospace company built its $750 million non-union plant in Charleston, S.C, rather than adding it to its unionized operations in Washington state, in retaliation for repeated strikes. Boeing denies the allegation.

A key piece of evidence in the case is a videotaped interview that Boeing Executive Vice President Jim Albaugh gave to the Seattle Times. In it, he explained the decision to put the assembly plant in South Carolina, saying: “The overriding factor was not the business climate, and it was not the wages we’re paying people today. It was that we can’t afford to have a work stoppage every three years.”

Albaugh added: “We can’t afford to continue the rate of escalation of wages as we have in the past. You know, those are the overriding factors. And my bias was to stay here.”

Solomon decided that Boeing’s decision to add jobs in South Carolina was “motivated by a desire to retaliate for past strikes and chill future strike activity.”

Boeing says that concern about strikes was only part of their rationale for opening the South Carolina plant. The company says that other reasons include lower labor costs and taxes, as well as financial incentives offered by South Carolina.

Moreover, the company said, while it added 1,000 jobs in South Carolina, it has also expanded its unionized workforce in Washington state. Solomon countered that many of those jobs in Washington could be temporary.

The case has been before an administrative-law judge since June. Lawyers are wrestling over procedural matters and no substantive testimony is expected for months. And once the judge makes a decision, the case is almost certain to be appealed to the full NLRB and then to the federal courts.

In the meantime, Solomon, 61, an Arkansas native who started out as a field examiner with the NLRB in 1972, has made peace with his newfound notoriety. He knows the furor that has erupted since he filed the Boeing case has extinguished any chance he had for being confirmed as the NLRB’s permanent general counsel. He can serve as long as the president would have him in an acting role, but once the job is over, he says he plans to retire from the NLRB.

The case, he said, “has changed my life. I have gone from a totally career person for 38 years to somebody who is a highly political person . . . that is just a whole different way of being.”