Who serves as the current Chief Justice of the United States?

The Chief Justice of the United States is responsible for overseeing the Supreme Court and ensuring its smooth operation. John Roberts has held this position since September 29, 2005. As Chief Justice, Roberts also has significant influence over the court's agenda and its deliberations, as well as the ability to assign opinions in cases where he is in the majority. His leadership has shaped various important rulings on issues ranging from health care to campaign finance.

The other choices provided are notable figures in the Supreme Court but do not hold the title of Chief Justice. Ruth Bader Ginsburg, who passed away in September 2020, was renowned for her work in advocating for gender equality and civil rights. Clarence Thomas is the longest-serving current justice, having been appointed in 1991, known for his originalist views. Samuel Alito, appointed in 2006, is recognized for his conservative judicial philosophy. However, none of these justices occupies the role of Chief Justice, which specifically belongs to John Roberts.