The Supreme Court on Monday is set to hear a bitter dispute between Republicans and the White House over whether President Obama exceeded his authority when appointing members to the National Labor Relations Board during a congressional recess.

The justices’ decision could cast a legal cloud over hundreds of rulings by the board, which resolves complaints of unfair labor practices and conducts elections for labor union representation.

The case, NLRB v. Noel Canning, centers around recess appointments Obama made to the labor board. In January 2012, Obama appointed three members to the board when the Senate was on break. Presidents can circumvent required Senate approval if the chamber is on recess, a move Obama deemed necessary because of repeated GOP blocks of his nominations to the panel.

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