Ronald E. Meisburg, a Republican and former general counsel for the National Labor Relations Board, predicted that if a Republican-controlled House cripples labor-backed legislative efforts to make it easier for workers to unionize, the Democratic-controlled labor board might take administrative steps. Mr. Meisburg noted that one Democratic labor-board member recently proposed making a change in the timing of workplace elections after employees file a petition to hold a unionization vote, reducing the delay to just five or 10 days.