Let's start with a couple of references from the United States Constitution:
Article 1 Section 1 - All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives.
Article 3 Section 1 - The judicial Power of the United States shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish.
By legislative powers, in addition to funding and other duties, the constitution means to create and modify law, subject to ratification by the Executive Branch, in the person of the President of the United States. By judicial power, the constitution gives courts the power to try federal cases (including disputes between states) and to interpret the constitutionality of laws. It is very clear to any reader that these powers do not include any provision for the judiciary to create law. In the last few decades, a slick way of writing unpopular law has emerged. Any party who has an agenda which will not be supported by the elected legislators can bypass the legislative process by filing a legal action with a sympathetic judge. The judge then issues an opinion that favors the plaintiff and it essentially becomes law. Even worse, the judge can strike down existing law and tell the legislature what kind of interpretation the judge will allow to stand, which makes the legislators redundant and powerless. It that case, the judge is clearly creating the law. Since the constitutionality of law is subject to review of the judiciary, and the judiciary is making the law, it should be fairly obvious that a judge is not going to strike down his or her own interpretation of the law. This process is usually referred to as “judicial activism”. It allows judges to do whatever they want to without regard to precedent or the desires of the elected representatives of the people. One needs to look no further than the historically astonishing opinions of the Ninth Circuit Court of Appeals in California for many examples. Not coincidently, the Ninth Circuit has more opinions reversed by the US Supreme Court than any other circuit.
Judicial activism has been responsible for a number of liberal causes becoming law. The recent same sex marriage opinion in California was created despite a 61% recent defeat of same sex marriage by the population of California in a vote. Roe versus Wade, the famous abortion decision, was decided based on a constitutional right to privacy which was created out of thin air by the Supreme Court. Under the theory of judicial activism, judges are free to do anything they want and, unlike elected legislators, there is nothing voters can do about it once they are in office. In fact, the legislature becomes powerless and useless.
Part of the Democratic push for the White House is that Justice John Paul Stevens is 88 years old and Justice Ruth Bader Ginsburg is 75 years old. In fact, the liberal justices are significantly older than the conservative justices. With a Democratic majority in the Senate and a Democratic President, the liberal wing of the Democratic Party will push for extremely liberal activist replacements should those justices retire or pass away. Additionally, the Democratic majority has been “running out the clock” by refusing to hold hearings of dozens of nominated judges so that if the next President is Democratic, all those nominations can be squashed and replaced by activists. Since the liberal agenda cannot be supported by legislation, the judiciary is used to create it.
The Republicans, on the other hand, are pushing for the Presidency so that more “strict constructionist” judges will be in place. Conservatives feel that by replacing even one of the liberal justices (Justices Stevens, Ginsburg, Breyer, or Souter), the direction of the court will be shifted. Chief Justice Roberts and both Justices Alito and Thomas are in their 50s. Only Justice Scalia, of the conservatives, is significantly older (72). Justice Kennedy, thought to be in the middle, is 71.
Since the court is currently thought to be four liberal, four conservative, and one swing vote, one new appointment could make a substantial difference to the make up of the court. Liberals are more anxious because of the ages of the liberal justices.
The choice in candidates is pretty clear. Barack Obama said in a recent statement, "We need somebody who's got the heart, the empathy, to recognize what it's like to be a young teenage mom. The empathy to understand what it's like to be poor, or African-American, or gay, or disabled, or old. And that's the criteria by which I'm going to be selecting my judges." Therefore legal expertise and experience apparently have no place in evaluation of judicial nominees, as long as they support his political beliefs. John McCain said that he thought that "abuse of judicial authority" had continued unchecked. "The result, over many years, has been a series of judicial opinions and edicts wandering farther and farther from the clear meanings of the Constitution,"
It is interesting that both Hillary Clinton and Barack Obama voted against the confirmation of both Justice Samuel Alito and Chief Justice John Roberts despite their stellar credentials and qualifications. Clearly their votes were agenda driven on not based on qualifications. John McCain voted to approve both nominees.
Despite the little political and media attention paid up to this point, judicial nominations might be the single most lasting result of the next President.