With Wilma Liebman's departure as the National Labor Relations Board chairwoman in late August, when her term expired, the five-member board is now down to three members, the minimum needed to issue major rulings. But that number could be down to two by 2012.

“It's just so uncertain what's going to happen with the [board's] composition,” says Denise Gold, the Associated General Contractors of America's associate general counsel.

Board member Craig Becker, a Democrat, is serving under a recess appointment that extends only until the end of December. President Obama has nominated Becker twice for full NLRB terms, but a Senate vote on Becker was blocked last year because of bitter opposition from business groups that view him as too pro-union. That makes Becker's confirmation to a full term iffy. Meanwhile, Republican Terence Flynn was nominated to the board in January, but the Senate hasn't voted on him yet.

If Flynn is not confirmed and Obama does not make another recess appointment by December, the NLRB will have just two members, which would complicate rule-making. In 2010, the Supreme Court invalidated NLRB decisions made with only two board members voting.

Organized labor viewed Liebman as an ally. “Wilma's loss is a big one,” says Laurence Cohen, International Brotherhood of Electrical Workers' general counsel. Cohen says another Democrat could be appointed during a congressional recess by 2012, bringing it back to three members.

Meanwhile, key construction issues remain before the board. Unions are focused particularly on cases that involve “salting”—a tactic in which a paid union staffer goes to work for a non-union company, intending to unionize it.

Cohen says that, during the George W. Bush administration, the NLRB issued at least three major salting decisions in employers' favor. He adds, “The Bush board decided it didn't like salting and was going to make it as difficult for construction unions as possible.”

Construction industry groups are watching regulations the NLRB proposed in June 2011 that would shorten the time during which a representation election would be held. “We're gravely concerned about it,” says Geoff Burr, Associated Builders and Contractors vice president of government affairs. “It's one of the things we predicted would take place if President Obama were elected—that they would attempt to achieve the goals of [the Employee Free Choice Act] through other means—and that's exactly what this is.” That bill, which failed in the Senate during the last Congress, would make it easier for workers to organize by letting them sign a card, rather than voting by secret ballot.