The Supremacy Clause of the United States Constitution (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it, and treaties made under its authority, constitute the supreme law of the land.
 It provides that state courts are bound by the supreme law; in case of conflict between federal and state law, the federal law must be applied.
 Even state constitutions are subordinate to federal law.
 In essence, it is a conflict-of-laws rule specifying that certain national acts take priority over any state acts that conflict with national law.
 In this respect, the Supremacy Clause follows the lead of Article XIII of the Articles of Confederation, which provided that "Every State shall abide by the determination of the United States in Congress Assembled, on all questions which by this confederation are submitted to them."
 A constitutional provision announcing the supremacy of federal law, the Supremacy Clause assumes the underlying priority of federal authority, at least when that authority is expressed in the Constitution itself.
 No matter what the federal government or the states might wish to do, they have to stay within the boundaries of the Constitution.
 This makes the Supremacy Clause the cornerstone of the whole American political structure.
Buckley v. Valeo, 424 US 1 (1976) is a US constitutional law Supreme Court case on campaign finance.
 A majority of judges held that limits on election spending in the Federal Election Campaign Act of 1971 §608 are unconstitutional.
 In a "per curiam" (by the Court) opinion, they ruled that expenditure limits contravene the First Amendment provision on freedom of speech because a restriction on spending for political communication necessarily reduces the quantity of expression.
 It limited disclosure provisions and limited the Federal Election Commission's power.
 Justice Byron White dissented in part and wrote that Congress had legitimately recognized unlimited election spending "as a mortal danger against which effective preventive and curative steps must be taken."
Randall v. Sorrell, 548 U.S. 230 (2006), is a decision by the Supreme Court of the United States involving a Vermont law which placed a cap on financial donations made to politicians.
 The court ruled that Vermont's law, the strictest in the nation, unconstitutionally hindered the citizens' First Amendment right to free speech.
 A key issue in the case was the 1976 case "Buckley v. Valeo", which many justices felt needed to be revisited.
Ableman v. Booth, 62 U.S. 506 (1859) , was a United States Supreme Court case in which the Court held that State courts cannot issue rulings on federal law that contradict the decisions of federal courts, overturning a decision by the Supreme Court of Wisconsin.
 The Supreme Court held that under the Constitution, the federal courts have the final power to decide cases arising under the Constitution and federal statutes, and that the States do not have the power to overturn those decisions.
 Thus, Wisconsin did not have the authority to nullify federal judgments or statutes.
Foster v. Chatman, 578 U.S. ___ (2016), was a United States Supreme Court case in which the Court held that the state law doctrine of "res judicata" does not preclude a "Batson" challenge against peremptory challenges if new evidence has emerged.
 The Court held the state courts' "Batson" analysis was subject to federal jurisdiction because "[w]hen application of a state law bar 'depends on a federal constitutional ruling, the state-law prong of the court’s holding is not independent of federal law, and our jurisdiction is not precluded,'" under "Ake v. Oklahoma".
Martin v. Hunter's Lessee, 14 U.S. 304 (1816) was a landmark United States Supreme Court case decided on March 20, 1816.
 It was the first case to assert ultimate Supreme Court authority over state courts in civil matters of federal law.
Federal common law is a term of United States law used to describe common law that is developed by the federal courts, instead of by the courts of the various states.
 The United States is the only country to combine the creation of common law doctrines with a complete federalism, wherein the national supreme court has virtually no power to review state court decisions to determine whether the state courts have followed state laws.
 The High Court of Australia is sometimes said to have federal common law, but because all state and territorial courts are directly appealable to the High Court, this is indistinguishable from a general common law.
 In contrast, the United States Supreme Court has effectively barred the creation of federal common law in areas traditionally under the authority of state courts.
 Nevertheless, there are several areas where federal common law continues to govern.
Francis Ralph "Frank" Valeo (January 30, 1916 – April 9, 2006) was the Secretary of the United States Senate and "ex officio" member of the Federal Election Commission.
 He was the defendant/appellee for the Federal government of the United States in Buckley v. Valeo, 424 U.S. 1 (1976), in which the Supreme Court of the United States upheld federal limits on campaign contributions.
Citizens Against Rent Control v. City of Berkeley, 454 U.S. 290 (1981), was a case in which the Supreme Court of the United States invalidated a California law that set limits on contributions to ballot issue campaigns.
 The ruling relies heavily on the Court's earlier decisions in Buckley v. Valeo, holding that limits on contributions to political candidates implicate the First Amendment, and First National Bank of Boston v. Bellotti, holding that the state governments have no compelling interest in limiting spending on speech about ballot issues.
The judiciary of Uruguay is a branch of the government of Uruguay that interprets and applies the laws of Uruguay, to ensure equal justice under law, and to provide a mechanism for dispute resolution.
 The legal system of Uruguay is a civil law system, with public law based on the 1967 Constitution, amended in 1989, 1994, 1997, and 2004.
 The Constitution declares Uruguay to be a "democratic republic", and separates the government into three equal branches, executive, legislative and judicial.
 Private relationships are subject to the Uruguayan Civil Code, originally published in 1868.
 The Constitution defines the judiciary as a hierarchical system courts, with the highest court being a five-member Supreme Court, who are appointed by the executive branch of the government, for ten-year terms.
 The Supreme Court appoints the judges of most of the lower courts.
 Below the Supreme Court, there are sixteen courts of appeal, each of which has three judges.
 Seven of the courts of appeal specialize in civil matters, four specialize in criminal matters, three cover labour law, and two focus on family matters.
 At the lowest tier are justices of the peace and courts of first instance specialized in administrative, civil, criminal, customs, juvenile, and labour cases.
 Although the hierarchy, all of them are functionally and structurally impartial, that is, the tribunal should not be interested in the object of the particular case, and the higher tribunal does not impose a behaviour nor precedent to the lower ones.
 There are also separate courts for auditing, elections and the military.

Question: In between Martin v. Hunter's Lessee and Buckley v. Valeo which was the first case to assert ultimate Supreme Court authority over state courts in civil matters of federal law?
Answer: Martin v. Hunter's Lessee