What grants federal administrative agencies the authority to act?

Federal administrative agencies derive their authority to act primarily from their enabling statutes. These statutes are specific laws passed by Congress that establish the agency, outline its powers, and define the scope of its authority. They serve as a legal foundation for the agency's operations by specifying what functions the agency can perform, what regulations it can create, and the areas it can oversee.

Enabling statutes also provide the framework within which the agency must operate, ensuring that its actions align with the legislative intent of Congress. This legal basis is crucial because it limits the agency’s powers to what has been granted by law, helping ensure accountability and adherence to the rule of law in the administrative process.

Other choices, such as executive orders or congressional funding, may influence or affect an agency's operations but do not grant the agency its core authority to act. Judicial rulings can impact how agencies operate but do not create their authority; rather, they interpret existing laws and actions taken by those agencies. Thus, the enabling statute is the fundamental source of power for federal administrative agencies.