State v. Cameron
In State v. Cameron, 2 Chand. 172, 2 Wis. 490 (1850), the Court upheld the trial court's decision to deny a defense request to exercise an unused peremptory challenge after both the prosecution and the defendant had accepted the jury, but before it was sworn. See 2 Pin. at 495-96.
The court relied on cases from other jurisdictions that held as a matter of law that "the practice is not to allow a defendant in a criminal proceeding to challenge a juror peremptorily, after he had been accepted ...." 2 Pin. at 496.
The court noted, however, that the "practice is different in different states, and has not been uniform in the same courts." Id.