In Swenson, Warden v. Bosler (1966), the United States Supreme Court ruled in favor of Bosler, a prisoner who had been denied habeas corpus relief by lower courts. The case revolved around whether or not Bosler's constitutional rights were violated during his trial for robbery in Missouri state court due to ineffective assistance of counsel and denial of right to appeal. The Supreme Court held that these allegations presented federal constitutional questions which should have been considered by the District Court on their merits rather than being dismissed summarily without an evidentiary hearing as they were substantial in nature. Therefore, it was decided that the dismissal was improper and remanded the case back to district court for further proceedings consistent with its opinion.

In the case of Swenson, Warden v. Bosler (1966), there was no recorded dissenting opinion. The Supreme Court ruled unanimously in favor of Bosler, holding that his Sixth Amendment right to counsel had been violated when he was not provided with an attorney during a critical stage of his prosecution for robbery. The court's decision hinged on its interpretation of the term "criminal prosecutions," which it held included all stages from arraignment through trial and sentencing, including appeals as a matter of right.