In NLRB v. A.J. Tower Co., 329 U.S. 324 (1946) the United States Supreme Court upheld the NLRB's policy prohibiting post-election challenges on an abuse-of-discretion standard. A.J. Tower Co., 329 U.S. at 332-33. A.J. Tower Co. involved a collective bargaining election under the National Labor Relations Act, and the election was conducted in accordance with an agreement between the union and the respondent, which provided for challenges of the voters' eligibility before or at the time of voting. Id. at 325-26. The agreement designated a director to investigate and report on challenges. Id. at 326. The respondent challenged a voter's eligibility four days after the election on the ground that she was not an employee and therefore was ineligible to vote. Id. at 327. In the closed setting of an NLRB election, after setting forth the above-quoted policy statements, the Supreme Court upheld the denial of the challenge based on the NLRB's general rule that a ballot cannot be challenged after it "has been cast without challenge and its identity has been lost." Id. at 332.