Fowler (defendant), who had stopped filing federal income tax returns in 1953, was eventually indicted for willful failure to pay income tax for the years 1971 to 1975. Fowler represented himself at his trial and sought to take the stand and testify. The court, however, did not allow Fowler to testify because he refused to take the oath or otherwise affirm that he would tell the truth in his testimony. While the court was willing to accept a statement from Fowler that “I state that I will tell the truth in my testimony,” Fowler would only agree to make statements such as “I am a truthful man,” and “I would not tell a lie to stay out of jail.” Fowler was convicted on all counts and appealed his conviction. Fowler, who obtained counsel for the appeal, asserted, inter alia, that the trial court had erred by not permitting him to testify at trial.