Petitioners (Mayo) offer residency programs to doctors who have graduated from medical school and seek additional instruction in a chosen specialty. Those programs train doctors primarily through hands-on experience. Although residents are required to take part in formal educational activities, these doctors generally spend the bulk of their time-typically 50 to 80 hours a week-caring for patients. Mayo pays its residents annual "stipends" of over $40,000 and also provides them with health insurance, malpractice insurance, and paid vacation time. The Federal Insurance Contributions Act (FICA) requires employees and employers to pay taxes on all "wages" employees receive and defines "wages" to include "all remuneration for employment." FICA defines "employment" as "any service . . . performed . . . by an employee for the person employing him, but excludes from taxation any "service performed in the employ of a school, college, or university if such service is performed by a student who is enrolled and regularly attending classes at the school." Since 1959, the Treasury Department has construed the student exception to exempt from taxation students who work for their schools "as an incident to and for the purpose of pursuing a course of study." In 2004, the Department issued regulations providing that "[t]he services of a full-time employee"-which includes an employee normally scheduled to work 40 hours or more per week-"are not incident to and for the purpose of pursuing a course of study." The Department explained that this analysis "is not affected by the fact that the services may have an educational, instructional, or training aspect." The rule offers as an example a medical resident whose normal schedule requires him to perform services 40 or more hours per week, and concludes that the resident is not a student. Mayo filed suit asserting that this rule was invalid, and the District Court agreed. The Eighth Circuit reversed. On appeal to the U.S. Supreme Court, the issue was whether doctors who serve as medical residents are properly viewed as "students" whose service Congress has exempted from FICA taxes. Should the Treasury Department's interpretation prevail? Do you believe that the resident doctors should be exempt from paying FICA taxes? What is the rationale for your opinion? [Mayo Foundation for Med. Educ. & Research v. United States, 562 U.S. 44 (2011).]