In the 1966 case of Spencer v. Texas, the United States Supreme Court upheld a Texas statute allowing prior convictions to be presented during sentencing in criminal trials. The appellant, Spencer, argued that this practice violated his Fourteenth Amendment rights by prejudicing jurors and denying him a fair trial. However, the court ruled 8-1 against Spencer's claim stating that it was within states' rights to design their own procedures for conducting trials and determining sentences as long as they did not violate "fundamental fairness" or "a specific prohibition in the Bill of Rights." The majority opinion held that presenting evidence of past crimes does not inherently prejudice juries against defendants nor deny them due process under law. This ruling affirmed states' authority over their own judicial processes while also setting precedent for how far those powers can extend without infringing on constitutional protections.

In the dissenting opinion for Spencer v. Texas, Justice William O. Douglas argued that prior convictions should not be used to determine sentencing in a current case as it violates the defendant's right to a fair trial under the Fourteenth Amendment's Due Process Clause. He believed that introducing evidence of past crimes could bias jurors and prevent them from making an impartial decision based solely on the facts presented in the current case. Furthermore, he contended that this practice is fundamentally unfair because it assumes guilt based on past behavior rather than present evidence. In his view, using previous convictions as part of sentencing procedures undermines one of our legal system’s most important principles: everyone is presumed innocent until proven guilty beyond reasonable doubt.