In Proctor v. Warden, Maryland Penitentiary (1977), the petitioner, Proctor, was convicted of murder in a state court and sentenced to life imprisonment. He appealed his conviction on grounds that he had been denied effective assistance of counsel due to his attorney's failure to object to certain evidence introduced at trial which allegedly violated his Fourth Amendment rights against unreasonable searches and seizures. The Supreme Court held that even if the attorney’s performance was deficient for not objecting, there is no constitutional right to an error-free trial or perfect representation by counsel; rather only a fair trial with competent counsel is guaranteed under the Sixth Amendment. Therefore, it must be shown that any errors made by defense counsel were so serious as to deprive defendant of a fair trial before relief can be granted on this basis.

The dissenting opinion in the case of Proctor v. Warden, Maryland Penitentiary argued that the majority's decision to deny habeas corpus relief was incorrect. The dissent believed that there were significant issues with how evidence had been obtained and used during Proctor's trial, which could have potentially violated his constitutional rights. Specifically, they pointed out problems related to a search warrant and its execution - arguing it was overly broad and thus unconstitutional - as well as concerns about an alleged confession by Proctor being admitted into evidence despite questions over its voluntariness. They felt these factors should have led to granting habeas corpus relief for Proctor rather than upholding his conviction.