A U.S. Federal Court has ruled that charter schools in Louisiana must acknowledge and bargain with teacher unions. In 2016, the United Teachers at New Orleans was asked by the teachers of International High School of New Orleans to represent them in contract negotiations. Voice of International Business and Education, the holder of the charter, had denied the request for representation, stating that in order to collectively bargain, the union needed the approval of the employer. Eventually, the court ruled that Voices is not a political subdivision of the state, and thus is not exempt from the ruling of the National Labor Relations Board.
See "Louisiana charter schools must recognize and bargain with teacher unions, court decides", Will Sentell, The Advocate, September 27, 2018