The U.S. Supreme Court is expected to hand down some major legal decisions over the next several weeks before its annual term concludes at the end of June. But, the Bush administration and opposition Democrats are also preparing for the possibility of a vacancy on the high court sometime in the near future.

One case yet to be decided that has generated intense international interest involves 51 Mexicans who have been sentenced to death in Texas and several other states.

The International Court of Justice in The Hague says they should be given new hearings because they were denied access to diplomats from their home country.

The Bush administration agreed to have the cases reviewed by state courts in Texas, but state officials there oppose the request and the high court has been asked to rule on the case.

The United States has since withdrawn from the protocol that allowed the international tribunal to hear such cases.

Another eagerly awaited decision involves the question of whether displays of the biblical Ten Commandments on government property violate the U.S. Constitution's ban on government endorsement of religion.

Rulings are also expected in cases that involve the legality of using marijuana for medical reasons and in a dispute over who should be held accountable for the illegal copying of music and movies on the Internet.

But the end of the court's term in June could also bring a vacancy on the high court for the first time in more than ten years.

Chief Justice William Rehnquist is battling thyroid cancer and if he were to step down, President Bush would have an opportunity to appoint his first Supreme Court justice.

Supreme Court nominees must be confirmed by the Senate, which is already embroiled in a dispute between majority Republicans and opposition Democrats over several of the president's nominees for vacancies on federal appeals courts.

Many political and legal analysts believe the current Senate battle over judges is a preview of what might happen if a vacancy opens up on the Supreme Court.

Stephen Wermiel is a longtime observer of the Supreme Court and a professor at American University's Washington College of Law.

"I do not think there is anybody on any list [of potential nominees] that will not lead to some kind of fight," he said. "The [political] stakes are too high, there are too many constituent groups with too much interest in where the court is headed on all different sides of the political spectrum, and so I do not see any way to avoid having there be a real battle."

Supreme Court nomination fights are often intense because justices serve for life and can have a lasting impact on the high court. It is also the kind of appointment that presidents tend to see as an important part of their legacy long after they have left office.