Military aircraft manufacturer Republic Aviation Corporation (Republic) (defendant) had a rule prohibiting solicitation of any kind at its plant. By 1943, the plant employed thousands of workers who commuted from all over Long Island to work long hours in wartime production. Republic fired one employee for passing out union application cards during lunch breaks and three others who wore union steward buttons when a union was trying to organize the plant, claiming they violated the no-solicitation rule. The National Labor Relations Board (NLRB) (plaintiff) found that Republic violated the employees’ rights under the Wagner Act. The NLRB ordered Republic to reinstate the employees and rescind the no-solicitation rule with respect to union solicitation and activity on an employee’s own time. Republic petitioned for review, arguing no evidence showed that Republic interfered with or discouraged union organization or that the plant’s location made union solicitation elsewhere unlikely to reach prospective union members. Republic also argued that it applied the rule equally to all solicitation, not just soliciting union membership, but the appellate court affirmed the NLRB’s decision. The Supreme Court consolidated the appeal with another raising similar issues and granted review.