Herrera and his coworkers tried again to get Teamsters union chiefs out of their workplace this summer by filing a “decertification petition” with the NLRB. Herrera’s petition, filed on August 30, contained signatures from enough of his coworkers to trigger an NLRB-supervised “decertification election,” a secret-ballot election after which union officials lose monopoly bargaining power if a majority of workers vote to remove them.