The judiciary is often called the third branch of government. Why, you might ask, if it's so important, does the Court come in last in the American tri-partite system? In part, this designation is the result of the federal court system having been outlined in Article III of the Constitution. (Article I concerns the legislature, and Article II addresses the executive branch.) But Article III is also remarkably short and makes the judicial branch seem almost like an afterthought.
Checks and balances
One of the chief architects of the Constitution, Alexander Hamilton, believed that that the Supreme Court, lacking both money and a militia, would be the weakest of the three branches. But Hamilton also knew that the government needed a police force to ensure that the two elected branches, the legislature and the executive, did not overstep their bounds in an effort to hang onto power. Someone had to make sure that the delicate dance being performed between the people's representatives and their leader would not interfere with the smooth running of the country or — more importantly, perhaps — violate the Constitution. The party ultimately responsible for maintaining the government's checks and balances, assuring that none of the branches abuses its authority, is the Supreme Court.
The three-part structure of federal government results in what is also confusingly called the separation of powers. The three branches are said to be both independent and interdependent. In reality, the separate branches are probably more blended than individual. Congress holds the quasi-judicial impeachment power that it can use to check both presidents and federal judges, for example. The glue that holds the parts together is the party system, which enables — and encourages — Republican presidents to work closely with Republican legislators and to nominate Republicans to sit on federal courts.
Once those Republicans take their seat on the high bench, however, presidents have no real control over them — as more than one chief executive has learned to his dismay. Federal judges, including Supreme Court justices, have what amounts to lifetime tenure and a guaranteed salary. Although justices can theoretically be removed from office by impeachment, none ever has been. The last time Congress attempted to pull this off was two centuries ago. The attempt failed, in the process proving the point that little short of criminal behavior could result in judicial removal. Political views — and especially personal judicial views — are plainly off limits to those who might wish to impeach a hostile jurist. Congress can overturn Supreme Court decisions only by means of the cumbersome process of constitutional amendment. Such efforts have succeeded exactly four times in the history of the republic. In each instance, it was the Supreme Court that determined the meaning and application of the amendment.
Judicial review
The federal judiciary is arguably the most independent of the three branches of federal government, the one least accountable to the others and the one that always has the last word. The reason for this unique status is judicial review, which is in essence the power to say what the law is. The federal bench, and the Supreme Court in particular, is the only branch of the federal government endowed with the ability to interpret the Constitution. In one fell swoop, for example, the Court declared in Roe v. Wade that abortion on demand is, under certain circumstances, a right guaranteed by the Constitution. Had abortion on demand been legislated, it would have taken coordination and agreement among the House of Representatives, the Senate, and the president — a cumbersome process, to be sure. And then, if someone had challenged a law granting a woman's right to choose (and surely someone would have), it would have been up to the federal courts to decide whether such a law passed constitutional muster.
The principle of judicial review was established by — what else? — a Supreme Court case. In what some commentators call the definitive Supreme Court decision, the 1803 Marbury v. Madison opinion, Chief Justice John Marshall wrote, "It is emphatically the province and duty of the judicial department to say what the law is." And judicial review permits the Supreme Court to rule both on actions of the other branches of federal government and on decisions of state courts concerning constitutional interpretation.
