<P> The Rehnquist Court (1986--2005) was noted for its revival of judicial enforcement of federalism, emphasizing the limits of the Constitution's affirmative grants of power (United States v. Lopez) and the force of its restrictions on those powers (Seminole Tribe v. Florida, City of Boerne v. Flores). It struck down single - sex state schools as a violation of equal protection (United States v. Virginia), laws against sodomy as violations of substantive due process (Lawrence v. Texas), and the line item veto (Clinton v. New York), but upheld school vouchers (Zelman v. Simmons - Harris) and reaffirmed Roe's restrictions on abortion laws (Planned Parenthood v. Casey). The Court's decision in Bush v. Gore, which ended the electoral recount during the presidential election of 2000, was especially controversial . </P> <P> The Roberts Court (2005--present) is regarded by some as more conservative than the Rehnquist Court . Some of its major rulings have concerned federal preemption (Wyeth v. Levine), civil procedure (Twombly - Iqbal), abortion (Gonzales v. Carhart), climate change (Massachusetts v. EPA), same - sex marriage (United States v. Windsor and Obergefell v. Hodges) and the Bill of Rights, notably in Citizens United v. Federal Election Commission (First Amendment), Heller - McDonald (Second Amendment) and Baze v. Rees (Eighth Amendment). </P> <P> Article III of the United States Constitution does not specify the number of justices . The Judiciary Act of 1789 called for the appointment of six "judges". Although an 1801 act would have reduced the size of the court to five members upon its next vacancy, an 1802 act promptly negated the 1801 act, legally restoring the court's size to six members before any such vacancy occurred . As the nation's boundaries grew, Congress added justices to correspond with the growing number of judicial circuits: seven in 1807, nine in 1837, and ten in 1863 . </P> <P> In 1866, at the behest of Chief Justice Chase, Congress passed an act providing that the next three justices to retire would not be replaced, which would thin the bench to seven justices by attrition . Consequently, one seat was removed in 1866 and a second in 1867 . In 1869, however, the Circuit Judges Act returned the number of justices to nine, where it has since remained . </P>

Who determines the number of justices on supreme court
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