Sam Gilliam (plaintiff), a noted artist and art instructor, was under psychiatric care and had a history of hospitalization for emotional disturbances. On a flight during a business trip, Gilliam had a severe reaction to a new psychiatric medication. Gilliam acted irrationally, repeatedly attempted to exit the airplane, and struck and injured another passenger. Gilliam faced federal criminal charges related to his behavior on the flight and was found not guilty by reason of insanity. Gilliam also settled a civil lawsuit brought by the passenger injured during the flight. On his federal tax return, Gilliam claimed business tax deductions for approximately $25,000 in legal fees for the criminal case and the settlement of the civil claim. The federal tax commissioner (commissioner) (defendant) disallowed Gilliam’s tax deduction. Gilliam petitioned the United States Tax Court for a redetermination.