Commerce Clause continues today. Advocates of states' rights such as constitutional scholar Kevin Gutzman have also criticized the court, saying it has misused the Fourteenth Amendment to undermine state authority. Justice Brandeis, in arguing for allowing the states to operate without federal interference, suggested that states should be laboratories of democracy. One critic wrote "the great majority of Supreme Court rulings of unconstitutionality involve state, not federal, law." Others see the Fourteenth Amendment as a positive force that extends "protection of those rights and guarantees to the state level." More recently, the issue of federal power is central in the prosecution of Gamble v. United States, which is examining the doctrine of "separate sovereigns", whereby a criminal defendant can be prosecuted by a state court and then by a federal court. Too slow British constitutional scholar Adam Tomkins sees flaws in the American system of having courts (and specifically the Supreme Court) act as checks on the Executive and Legislative branches; he argues that because the courts must wait, sometimes for years, for cases to navigate their way through the system, their ability to restrain other branches is severely weakened. In contrast, various other countries have a dedicated constitutional court that has original jurisdiction on constitutional claims brought by persons or political institutions; for example, the Federal Constitutional Court of Germany, which can declare a law unconstitutional when challenged. Too small The U.S. Supreme Court is the smallest (9 justices) of any major nation and could be expanded without a constitutional amendment. Some have argued that 9 justices is too small a number to represent the perspectives of more than 300 million people, and that the number of seats on the Supreme Court should be expanded, with Jonathan Turley, advocating for 19 justices. See also Judicial appointment history for United States federal courts List of courts which publish audio or video of arguments List of presidents of the United States by judicial appointments Lists of United States Supreme Court cases List of supreme courts by country List of pending United States Supreme Court cases Oyez Project Reporter of Decisions of the Supreme Court of the United States Selected landmark Supreme Court decisions Marbury v. Madison (1803, judicial review) McCulloch v. Maryland (1819, implied powers) Gibbons v. Ogden (1824, interstate commerce) Dred Scott v. Sandford (1857, slavery) Plessy v. Ferguson (1896, separate but equal treatment of races) Wickard v. Filburn (1942,