For businesses, it was the type of action they have feared from a National Labor Relations Board dominated by Democrats. For labor unions, it was the type of action they have hoped for. And for both, it may be a sign of things to come.

These fears and hopes were stirred last week when the labor board's top lawyer filed a case against Boeing, seeking to force it to move airplane production from a nonunion plant in North Charleston to a unionized one in Washington state. Boeing executives had publicly said they were making the move to avoid the kind of strikes the airplane maker had repeatedly faced in Washington; Lafe Solomon, the labor board's acting general counsel, said the company's motive constituted illegal retaliation against workers for exercising their right to strike.

The agency's unusually bold action angered business groups and some politicians, who said it was an unwarranted attempt by the government to interfere with a fundamental corporate decision.

But under President Barack Obama's appointees, the agency, including Solomon and his staff, have sought to reinterpret and more aggressively enforce the rules governing employers and employees, from what workers can say about their bosses on Twitter to the use of Internet and phone voting in union elections.

How much ultimately changes will depend in large part on the rulings made by the five-member board, led by Wilma Liebman, that sits atop the agency. That panel hears cases brought by the board's regional offices -- overseen by Solomon -- after employers, workers or unions file complaints.

Democratic-dominated boards often tilt toward unions and reverse the decisions of Republican- leaning boards, which usually tilt toward management, and vice versa. The current board -- made up of three Democrats and one Republican, with one vacancy -- is expected to reverse a Bush-era decision that stripped graduate teaching assistants at private universities of their right to bargain collectively. Labor experts also predict that the board will adopt a policy that makes it easier to organize nursing home workers by allowing unions to go after smaller units of workers inside those homes.

The biggest surprise has been the activist stance taken by Solomon, a career civil servant at the board for 39 years. He became acting general counsel in June 2010, and Obama nominated him to be the permanent general counsel last January. The Senate has not yet confirmed him to the post.

In the Boeing case, Solomon charged that the company had illegally moved some production work of the 787 Dreamliner passenger plane to South Carolina to punish workers for past strikes and to avoid future ones. The remedy proposed by Solomon has been denounced as extreme by many business leaders: that Boeing essentially abandon a $2 billion investment and 1,000 nonunion workers it hired in South Carolina and move the work back to its unionized Puget Sound facilities.

Outraged, the National Association of Manufacturers warned that if the agency won this case, "no company will be safe from the NLRB stepping in to second-guess its business decisions on where to expand."

Republican Sen. Jim DeMint, of South Carolina complained, "This is nothing more than a political favor for the unions who are supporting President Obama's re-election campaign."

The Boeing case was not the first time that Solomon has riled the business community and its Republican allies. He recently threatened to sue four Republican-dominated states -- Arizona, South Carolina, South Dakota and Utah -- in an effort to invalidate recently approved constitutional amendments that prohibit private sector workers from choosing a union by simply signing cards, a process known as card check.

He has also sought to extend the labor board's reach into the world of the Internet. He approved requests from regional labor board officials to bring complaints against businesses that punished employees for Facebook and Twitter posts, including one case against Reuters news service. Solomon has also proposed that electronic voting be used when workers decide whether they want to unionize their workplace -- a proposal that business groups maintain will make it easier for unions to coerce workers.

In an interview, Solomon, a 61-year-old Arkansas native, insisted that he was no radical. "My goal is to enforce the National Labor Relations Act," he said. That law, enacted in 1935, governs private sector workers' right to unionize as well as relations between tens of thousands of companies and employees.

Solomon, who has worked for board members of both parties, said this case was straightforward. "They had a consistent message that they were doing this to punish their employees for having struck and having the power to strike in the future," he said. "I can't not issue a complaint in the face of such evidence."

While the spotlight is on Solomon at the moment, people inside the agency and out expect that attention will soon move to the five-member board, whose decisions often have broad effect, much like court precedents.