Eleven years later, the Court refused to consider a federal district court's ruling that Taft-Hartley Act did not ban expenditure of union dues on communications with the public. Disputes over the constitutional and statutory status of union shop and agency shop agreements began almost immediately after the passage of the Taft-Hartley Act. In the Supreme Court's first major ruling on the issue in "Railway Employees' Dept. v. Hanson," 351 U.S. 225 (1956), the Court held that the union security provisions of the Railway Labor Act were constitutional, but withheld judgment as to "the validity or enforceability of a union or closed shop agreement if other conditions of union membership are imposed or if the exaction of dues, initiation fees or assessments is used as a cover for forcing ideological conformity or other action in contravention of the First or the Fifth Amendment." The ruling in "Hanson" appeared to call into serious question the viability of union shop agreements. Five years later, in "Machinists v. Street", 367 U.S. 740 (1961), the Court held that the Railway Labor Act "denies the authority to a union, over the employee's objection, to spend his money for political causes which he opposes." The high court also confronted the issue of remedy in "Machinists v. Street," and outlined several options which unions and employers might adopt as well as rejecting remedies which the district court in the case had chosen. The Supreme Court returned to the union security issue three more times in 1963. In "NLRB v. General Motors Corp.," 373 U.S. 734 (1963), the Court held that agency fees equal to dues are not prohibited by the National Labor Relations Act. Nonetheless, in "Retail Clerks v. Schermerhorn," 373 U.S. 746 (1963), the Court questioned whether an agency fee set at a level equal to member dues was unfair because it set collective bargaining fees higher for non-members than for members. After reargument, however, the Court in "Retail Clerks v. Schermerhorn," 375 U.S. 96 (1963), did not reach the issue again and instead decided the case on narrow procedural grounds (concluding that Florida's right-to-work law outlawed the union shop provision at issue). The Court further elaborated on the issue of remedies in "Railway Clerks v. Allen," 373 U.S. 113 (1963), allowing agency fee payers to opt out of all political expenditures rather than enunciate specific examples but refusing to allow them to act as a class.