In the 1979 case Hammett v. Texas, the United States Supreme Court reviewed a decision made by the Texas Court of Criminal Appeals. The petitioner, Hammett, was convicted for robbery in a state court and sentenced to life imprisonment due to his status as a habitual offender under Texas law. He appealed this conviction on grounds that he had been denied effective assistance of counsel because his attorney did not object when evidence from an illegal search was presented during trial. However, both the state appellate court and U.S Supreme Court rejected these claims. The Supreme Court held that even if Hammett's lawyer had objected to the evidence obtained through an unlawful search and seizure at trial, it would have made no difference in light of other overwhelming untainted evidence against him. Therefore, any error committed by defense counsel did not result in prejudice sufficient enough to affect the outcome or fairness of proceedings - thus failing to meet standards established for ineffective assistance claims under Strickland v Washington (1984). This ruling affirmed that defendants must show their attorneys' performance fell below professional norms and prejudiced their cases before they can claim ineffective assistance.

The dissenting opinion in Hammett v. Texas argued that the majority's decision was inconsistent with previous rulings of the Court, particularly those related to Fourth Amendment rights and protections against unreasonable searches and seizures. The dissenters believed that the police had violated these rights when they searched Hammett's car without a warrant or probable cause, merely on suspicion of illegal activity. They contended that this constituted an invasion of privacy which is not justified by law enforcement needs or societal interests. Furthermore, they disagreed with the majority's view that any evidence obtained during such a search could be used in court proceedings against him. This viewpoint held firm to upholding constitutional safeguards over procedural expediency.