Question: Were United States v. Nixon and Zelman v. Simmons-Harris both US Supreme Court cases?

 Issued on July 24, 1974, the ruling was important to the late stages of the Watergate scandal, when there was an ongoing impeachment process against Richard Nixon. United States v. Nixon, 418 U.S. 683 (1974), was a landmark United States Supreme Court decision which resulted in a unanimous 8–0 ruling against President Richard Nixon, ordering him to deliver presidential tape recordings and other subpoenaed materials to the District Court.  "United States v. Nixon" is considered a crucial precedent limiting the power of any U.S. president to claim executive privilege. <SEP> Hollingsworth v. Perry refers to a series of United States federal court cases that legalized same-sex marriage in the State of California.  The case began in 2009 in the U.S. District Court for the Northern District of California, which found that banning same-sex marriage violates equal protection under the law.  This decision overturned ballot initiative Proposition 8, which had banned same-sex marriage.  After the State of California refused to defend Proposition 8, the official sponsors of Proposition 8 intervened and appealed to the Supreme Court.  The case was litigated during the governorships of both Arnold Schwarzenegger and Jerry Brown, and was thus known as Perry v. Schwarzenegger and Perry v. Brown, respectively.  As "Hollingsworth v. Perry", it eventually reached the United States Supreme Court, which held that, in line with prior precedent, the official sponsors of a ballot initiative measure did not have Article III standing to appeal an adverse federal court ruling when the state refused to do so. <SEP> Zelman v. Simmons-Harris, 536 U.S. 639 (2002) , was a 5-4 decision of the United States Supreme Court that upheld an Ohio program that used school vouchers.  The Court decided that the program did not violate the Establishment Clause of the First Amendment even if the vouchers could be used for private, religious schools. <SEP> Stephen P. Halbrook is a Senior Fellow at the Independent Institute and an author and lawyer known for his litigation on behalf of the National Rifle Association.  He has written extensively about the original meanings of the Second Amendment and the Fourteenth Amendment (the latter as applied to Second Amendment rights).  He has argued and won three cases before the US Supreme Court: "Printz v. United States", "United States v. Thompson-Center Arms Company", and "Castillo v. United States".  He has also written briefs in many other cases, including the Supreme Court cases "Small v. United States" (pertaining to the Gun Control Act of 1968) and "McDonald v. Chicago".  In "District of Columbia v. Heller", he wrote a brief on behalf of the majority of both houses of Congress.  More broadly, his decades of research on the Second Amendment contributed to the intellectual foundation of the "Heller" decision.  He has written many books and articles on the topic of gun control, some of which have been cited in Supreme Court opinions ("Heller", "McDonald", "Printz v. United States").  He has testified before congress on multiple occasions.  Halbrook’s most important scholarly contribution, however, was the book "That Every Man Be Armed", originally published in 1986.  The book was the most thorough analysis of the legal history and original intent of the Second Amendment.