Final answer:
The 'tenth justice' unofficially refers to the Solicitor General of the United States, who has significant influence on the Supreme Court's decisions and legal arguments.
Step-by-step explanation:
The official who holds the unofficial title of the 'tenth justice' is the Solicitor General of the United States. This title reflects the significant influence that the Solicitor General has on the Supreme Court due to their role in presenting the government's views in cases before the Court.
The nickname arose because the Solicitor General participates in many of the cases before the Supreme Court and has an important role in shaping the legal arguments that become a foundational part of the Court's opinions
For instance, Justice Anthony Kennedy's written opinions often reflected the substantial power the Solicitor General has over the Court.
Despite the Supreme Court consisting of nine justices, the Solicitor General's position allows them to have a notable impact, akin to an additional justice.The official with the unofficial title of the 'tenth justice' is the Solicitor General.
The solicitor general is a high-ranking official in the U.S. Department of Justice who represents the federal government before the Supreme Court. Although not an actual justice, the solicitor general's opinions hold significant influence on the court's decisions.