In Barker v. Wingo, the U.S. Supreme Court was tasked with determining whether a five-year delay between arrest and trial violated the Sixth Amendment's guarantee of a speedy trial. The case involved Willie Mae Barker, who had been charged with murder in 1958 but wasn't tried until 1963 due to numerous continuances granted by the court at the request of his co-defendant's attorney. In its decision, handed down in 1972, the Supreme Court ruled that while an accused person does have a right to a speedy trial under the Sixth Amendment, this right must be balanced against other factors such as societal interests and prosecutorial difficulties which may justify delays. The court established four factors for lower courts to consider when evaluating potential violations: length of delay; reason for delay; defendant’s assertion or non-assertion of their right; and prejudice caused by delay on defendant’s ability to mount defense.

In the dissenting opinion for Barker v. Wingo, Justice Brennan disagreed with the majority's decision to not establish a specific time limit after which speedy trial rights are violated. He argued that without such a limit, it would be difficult to determine when an accused's right has been infringed upon. He also expressed concern about leaving this determination up to individual judges' discretion and believed that setting a clear standard would provide better guidance for lower courts and protect defendants' rights more effectively. Furthermore, he criticized the majority's reliance on factors like reason for delay or whether defendant asserted his right in determining violation of speedy trial rights as these could potentially excuse even egregious delays in bringing cases to trial.