In United States v. Delgado, 635 F.2d 889 (7th Cir. 1981), the Seventh Circuit explained the substance of a waiver colloquy and reversed the defendant's conviction because the colloquy was too sparse under the circumstances. Id. at 890.
Subsequent case law in the Seventh Circuit, however, has substantially narrowed Delgado.
In United States v. Rodriguez, 888 F.2d 519 (7th Cir. 1989), the Seventh Circuit explained that the Delgado warnings "are called for as a matter of prudence," rather than constitutional mandate, and asserted that "lesser (even no) warnings do not call into question the sufficiency of the waiver so far as the Constitution is concerned." Id. at 527.
The Seventh Circuit explained that it is necessary to look to the totality of the circumstances to ascertain whether a defendant's waiver was knowing, intelligent, and voluntary. See id. at 528.
In fact, under Supreme Court precedent, courts must not automatically reverse a conviction simply because a trial judge did not adhere to a prophylactic rule, such as administering a colloquy. See id.