In the 1970 case International Brotherhood of Boilermakers, Iron Shipbuilders, Blacksmiths, Forgers and Helpers, AFL-CIO v. Hardeman, the U.S Supreme Court ruled on a dispute involving union disciplinary actions against members who had crossed picket lines during a strike. The respondent was fined by his local union for crossing a picket line to work during an authorized strike. He sued in state court arguing that this fine violated his rights under federal labor law. The Supreme Court held that unions have the right to impose reasonable fines on their members as part of internal discipline without violating federal labor laws or policies provided they are not excessive or discriminatory and do not violate any specific provision of the Labor Management Reporting and Disclosure Act (LMRDA). This decision affirmed unions' authority to maintain discipline among their ranks while also ensuring protections for individual workers from arbitrary or punitive measures.

In the dissenting opinion for International Brotherhood of Boilermakers, Iron Shipbuilders, Blacksmiths, Forgers and Helpers v. Hardeman (1970), Justice Hugo Black argued that the majority's decision was a departure from established principles of federal labor law. He contended that the National Labor Relations Act (NLRA) should protect workers' rights to express their views on union matters without fear of retaliation by union leadership. The majority held that a fine imposed by a union on one of its members for crossing an unofficial picket line did not violate his free speech rights under Section 101(a)(2) of the Labor-Management Reporting and Disclosure Act (LMRDA). However, Justice Black disagreed with this interpretation; he believed it undermined Congress's intent in passing LMRDA to ensure democratic practices within labor organizations. Furthermore, he expressed concern about potential abuses if unions could punish members who disagree with official positions or actions.