The Federal Employees Liability Reform and Tort Compensation Act of 1988, known as the Westfall Act (28 U.S.C. § 2679), allows the Attorney General to certify that a federal employee acted within the scope of employment, automatically replacing the individual employee with the United States as defendant. Because the federal government cannot be sued for defamation under the Federal Tort Claims Act, Westfall certification effectively ends a defamation lawsuit. Courts review the certification de novo and can reject it if the conduct falls outside the scope of employment.