• Many different inferior courts serve below the Supreme Court within the federal judiciary
• Federal appeals courts review lower court rulings and sometimes pass cases on to the Supreme Court
• Special tribunals hear particular types of cases
• Military commissions have been controversial during War on Terror

Ultimately, it's appropriate that we tend to think of the Supreme Court as the judicial branch, rather than as one element of it. We imagine it to be on an equal plane as the executive and the legislative branches, and it is; the framers of the Constitution designed this court, and only this court, to be as powerful as the president and the Congress. Yet, just as the president depends largely on a variety of executive agencies and some fifteen cabinet departments to fulfill his duties, so too does the highest court in the land rely on a large system of inferior courts.

Let's recall that, though the Constitution established the creation of only one tribunal—the Supreme Court—it did vest Congress with the power to establish inferior courts. And so, through plenty of trial and error—remember all that back-and-forth over the whole Supreme Court size issue?—Congress settled on two separate categories of lower federal courts: the constitutional courts and the special courts.

Constitutional courts, also referred to as "regular courts" or "Article III courts," include District Courts, US Courts of Appeals, the US Court of Appeals for the Federal Circuit, and the US Court of International Trade. These tribunals have broad jurisdiction and, thus, hear the vast majority of cases tried within the federal judiciary. In fact, the federal judges that preside over these courts handle approximately 80% of the entire federal caseload. It's no surprise, then, that so many of these courts exist and that most operate out of various regions of the country, from the northeast to the southwest.

Most of these courts are District Courts, of which there are currently 94: at least one in each of the fifty states and Washington, D.C. and one to serve each of the four US overseas territories (Puerto Rico, the Virgin Islands, Guam, and the Northern Mariana Islands). As the primary trial courts within the federal judiciary, District Courts handle hundreds of thousands of cases per year, including a wide range of trials, both criminal—cases in which the defendant is tried for something that Congress has designated as a federal crime, such as mail fraud, counterfeiting, or bank robbery—and civil—cases that originate under bankruptcy, copyright, tax, or other federal statues. District Court rulings are usually final but can be appealed to one of 12 US Courts of Appeals. Only a rare handful of decisions are ever reviewed by the US Supreme Court.

Before Congress established the US Courts of Appeals in 1891, the Supreme Court heard all appeals from all federal district courts. Noticing that the Justices were getting buried in casework, Congress created one Court of Appeals for each of the nation's twelve judicial circuits. The judges presiding over these courts, unlike the District Courts, have only appellate jurisdiction, which helps limit the number of cases on their dockets. However, since the Courts of Appeals review decisions from the several special courts and a number of federal regulatory agencies in addition to those from the District Courts, they handle some 50,000 cases per year. US Court of Appeals rulings are usually final, but can, in rare instances, be reviewed by the Supreme Court.

Like the US Courts of Appeals, Congress created the US Court of Appeals for the Federal Circuit to help the Supreme Court shoulder the load of appeals that originate in the US Court of International Trade (another constitutional court created to hear civil disputes over trade-related laws) and in two types of special courts: the US Court of Federal Claims and the US Court of Appeals for Veterans' Claims. Rulings announced by the US Court of Appeals for the Federal Circuit are normally final, but a rare few have been reviewed by the US Supreme Court.

Along with these constitutional courts, or "regular courts", Congress has expanded the federal judiciary by creating several distinct tribunals with the power to try all those federal cases that fall outside the margins of "regular" lawsuits. These special courts include the US Court of Appeals for the Armed Forces, the Courts of the District of Columbia, the US Court of Appeals for Veterans' Claims, the US Court of Federal Claims, the US Tax Court, and the Territorial Courts. Also referred to as "legislative courts" and "Article I courts," these courts deal specifically with cases involving federal institutions such as the Internal Revenue Service, the Department of Veterans' Affairs, and the Armed Forces.

For instance, the Court of Federal Claims hears monetary lawsuits brought against the federal government. Before 1855, no suit could be levied against the government without its consent, but with the creation of this court, citizens gained the right to sue their government—but only before this special court. Plaintiffs unhappy with a ruling in the Court of Federal Claims can seek a review of the decision by the Court of Appeals for the Federal Circuit, a constitutional court.

Two additional special courts deal primarily with civil cases involving disagreements over money. The United States Tax Court, established by Congress in 1969 as a federal trial court, is responsible for deciding disputes between taxpayers and the Internal Revenue Service (IRS). The US Court of Appeals for Veterans' Claims, which has exclusive jurisdiction to review cases decided by the Board of Veterans' Appeals, was created to support military vets who have been, in some way, denied their claims for veteran's benefits.

The United States Court of Appeals for the Armed Forces is an appellate court that reviews court-martial decisions for members of the military. Courts-martial, or military tribunals, happen to be one of the earliest court systems established in the United States. Responsible for keeping the nation's armed forces in check, these courts try military officers, commanders, and other personnel charged with violating the rules and regulations of the US Armed Services. Congress created this Court of Appeals for the Armed Forces in 1950 to take on appeals from the courts-martial in a civilian tribunal; that is, one independent of the military establishment. Although this court, like the Tax Court, was originally set up as a tribunal independent of the federal judiciary, its decisions are subject to review by the Supreme Court.

Quite distinct from courts-martial and the Court of Appeals for the Armed Forces are Military Commissions. Still the most controversial of all the federal courts, these tribunals are instituted in times of war and on a case-by-case basis to try enemy combatants. A Military Commission, made up entirely of military officers with the power to charge, prosecute, convict, and sentence a defendant, can be initiated by the Defense Department and then approved by the president in his role as Commander in Chief of the US Armed Forces. Because Military Commissions operate outside the scope of conventional judicial rules and their decisions can only be appealed with the approval of the president (a major conflict of interest, many would argue), critics charge that their trials violate protections guaranteed by the US Bill of Rights. In recent years, Military Commissions organized to try terrorism suspects held in a special prison at Guantanamo Bay, Cuba have been especially controversial.

There you have it: the inner-workings of the judicial branch. Got it? Chances are you're still a little bit uncertain about how the whole thing works. That's exactly why we've prepared a whole series of articles dedicated to exploring the most groundbreaking Supreme Court cases, as well as the constitutional debates that have kept the federal judiciary busy for the two centuries. Now that you've pried open the machine and taken a look at each of its parts, you're prepared to dive into the laws and controversies that keep its cogs turning.