The U.S. Supreme Court case Nationwide Mutual Insurance Company v. Robert T. Darden (1991) revolved around the issue of whether an individual was an employee or independent contractor under the Employee Retirement Income Security Act (ERISA). Robert T. Darden, a former insurance agent for Nationwide Mutual Insurance Company, sued the company claiming he was entitled to pension benefits as per ERISA after his contract termination by Nationwide due to alleged breach of agreement terms and conditions. The court had to determine if Darden qualified as an "employee" under ERISA's definition which is vague and does not clearly differentiate between employees and independent contractors. The Supreme Court ruled in favor of Nationwide, stating that common-law agency test should be used to define who qualifies as an 'employee' under ERISA rather than relying on IRS guidelines or other statutory definitions from different contexts; this test considers factors such as hiring party's right to control manner and means by which work is accomplished among others. This ruling clarified how courts should interpret ambiguous employment status in relation with federal statutes unless Congress has explicitly defined it otherwise within specific legislation.

The dissenting opinion in the Nationwide Mutual Insurance Company v. Robert T. Darden case argued that the majority's decision to apply a common-law agency test to determine whether an individual is an employee under ERISA was incorrect and inconsistent with congressional intent. The dissenters believed that Congress intended for ERISA to have broad applicability, covering not only traditional employees but also individuals who are economically dependent on a business and subject to its control, regardless of how their relationship is labeled. They pointed out that other federal labor laws use this broader definition of "employee," which supports their interpretation of Congressional intent for ERISA as well. Therefore, they would have remanded the case back to lower courts for further proceedings using this broader standard.