The National Labor Relations Board will be poring over more than 400 decisions, from 2012 and 2013, in the wake of the U.S. Supreme Court's unanimous June 26 ruling that President Obama exceeded his authority in naming three members to the board during a three-day break between Senate sessions.

But the court's unanimity about that judgment veils a split. Five justices signed on to the majority opinion. The other four concurred that Obama overstepped his powers but said the majority should have gone much further in limiting presidential authority.

Gregory King, NLRB public-affairs office director, says the board issued 436 contested decisions from Jan. 31, 2012, to July 16, 2013, when the three appointees were on the board. Cases dealing with 100 of those actions are pending in federal appeals courts, King adds. NLRB Chairman Mark Gaston Pearce said in a statement that the board "is committed to resolving any cases affected by [the] decision as expeditiously as possible."

The ruling "jeopardizes the legal status" of those decisions, according to the Associated Builders and Contractors.

Denise S. Gold, Associated General Contractors of America associate general counsel, said via email that the NLRB decided several construction cases in that 2012-2013 span, but none "broke any major new ground."

However, during that time period, NLRB also decided several non-construction cases that have a significant impact on construction firms, Gold noted. They include the July 2012 Banner Health System decision, which, Gold says, held that "a company policy asking employees not to discuss ongoing internal investigations violates the National Labor Relations Act." Gold also notes the December 2012 "WKYC-TV case, in which the board overturned 50 years of precedent to hold that an employer signatory to a collective-bargaining agreement with a dues check-off provision must continue to deduct dues from employees' paychecks even after the agreement expires."

Further, Gold says the current board, which has a full complement of five Senate-confirmed members, "is free to effectively rubber-stamp those invalidated decisions and is likely to do so."

"The most immediate and practical impact of the Supreme Court's decision will likely … cause a substantial slowdown of processing and backlog of cases at the board as it reviews those cases," she says.