On 11/2/01, the D.C. Circuit ruled that the NLRB acts legally when it requires that employees in non-union workplaces be given the right to have a co-worker or other individual with them during an investigatory interview by an employer. Section 7 of the National Labor Relations Act protects the right of an employee to engage in concerted activities for the purpose of mutual aid or protection, and having a co-worker present during an investigatory interview is justifiable to ensure that the employer "does not initiate or continue a practice of imposing punishment unjustly." However, the court refused to apply the NLRB's revised interpretation retroactively in this case. It will be applied in future cases.The NAM and other groups filed an amicus brief on 5/15/01 objecting to the extension of so-called Weingarten rights of union employees to non-union workers, arguing that an individual non-union employee's representative does not represent the interests of the entire workplace.