Even if senators consider a nominee professionally qualified, they often debate his judicial philosophy. The term is code for political reliability. When Republicans praise a nominee's judicial philosophy, they often mean they are reasonably certain the nominee will agree with them. When Democrats raise questions about a Republican nominee's judicial philosophy, they are often expressing fear that the nominee will rule in a politically conservative fashion. Whatever party is in power usually declares that a nominee's judicial philosophy should not be questioned or considered grounds for rejection. Whatever party is in the minority usually argues the opposite — that gauging a nominee's judicial philosophy is a crucial part of gauging their qualifications for the bench.

The Constitution sets up a balance of power in government: Congress passes laws, the president executes them and the Supreme Court arbitrates any disputes. Conservatives argue that judicial rulings that have the effect of making social policy are an improper intrusion of the judiciary into legislative matters, deriding them as legislating from the bench. They point to Roe vs. Wade, the 1973 Supreme Court decision legalizing abortion nationwide, as a prime example.

What both Republicans and Democrats say they fear in a Supreme Court justice. Republicans don't want judges to be active in making rulings on social policy. Democrats don't want judges to be active in overturning existing rulings, especially in the areas of civil and reproductive rights.

What both Republicans and Democrats say they want in a Supreme Court justice. Republicans want judges to be restrained on issues of morality and social policy. Democrats want judges to be restrained in narrowing or overturning existing rulings, especially in the areas of civil and reproductive rights.

Also referred to by the Latin term stare decisis (STAIR-ee dee-SIGH-sis), which means to stand by a decision. It refers to the legal notion that the law is consistent over time, and that courts should follow the rulings of judges who came before them. When Democrats ask Republican nominees about their commitment to precedent, they are really asking whether the nominee has any qualms about overturning prior decisions unpopular with conservatives — in particular, Roe vs. Wade.

The phrase in the 1st Amendment that says "Congress shall make no law respecting an establishment of religion." Liberals generally interpret the establishment clause as calling for separation of church and state. Conservatives generally believe it means the government cannot establish a state religion, but that it permits most public expressions of religious faith.

The language in the Constitution granting Congress the power "to regulate commerce with foreign nations, and among the several states." The clause has been interpreted to permit Congress to pass much of the landmark civil rights, anti-discrimination and environmental legislation of recent decades, the logic being that those issues transcend state boundaries. Some conservatives feel the clause has been too broadly interpreted and have pursued several recent challenges before the Supreme Court. Liberals believe the current Supreme Court has been trying to narrow interpretations of the commerce clause and, by extension, much of the federal government's regulatory powers.

The word privacy does not appear in the Constitution, and some conservative jurists say that means the Constitution does not guarantee a right to privacy. Other scholars believe a right to privacy is implicit in other guarantees. For instance, the 4th Amendment prohibits "unreasonable searches and seizures"; the 14th Amendment guarantees the right to "due process of the law" before being deprived of rights or property; and the 9th Amendment says that the Bill of Rights should not be read to preclude other, unstated rights. The implied right to privacy was a central rationale for a number of controversial Supreme Court decisions, including the legalization of contraception, abortion and sexual acts between consenting adults, including gays. The debate over whether the Constitution guarantees a right to privacy is often a surrogate for the debate over those decisions.