With the Democratic Party regaining control of Congress for the first time since 1994, Democratic leaders should look to undo the effects the Bush administration has had on American workers. But that won't be easy, because one institution that remains solidly in Republican and anti-worker hands is the National Labor Relations Board, the country's chief arbiter of labor disputes.

Although nominally a quasi-judicial entity appointed by the president and empowered to adjudicate labor disputes, the NLRB actually sets the rules that govern those...