President Bush is expected to nominate a successor to retiring Justice Sandra Day O'Connor by the end of this month. But the battle over the first Supreme Court vacancy in 11 years is well under way.

Special interest groups on both ends of the political spectrum have been mobilizing for a Supreme Court confirmation fight for years.

Conservative groups, especially conservative Christian activists, are urging the president to nominate a conservative who shares their opposition to abortion and homosexual marriage.

The Reverend Ted Haggard heads the National Association of Evangelicals.

"An independent judiciary is important to maintain, but the judiciary has politicized itself. This is an opportunity to right a ship that has gone awry," he says.

Liberal activist groups also see the Supreme Court fight as a high stakes political battle.

Tom Matzie is with a group called, which has vowed to fight any attempt by the president to replace the centrist-leaning Justice O'Connor with a strong conservative.

"Definitely if the president tries to replace (Justice) O'Connor, a moderate, with an extremist, it will be the toughest fight over the Supreme Court in American history," Mr. Matzie says.

Some conservative groups have also signaled their opposition to the possibility that the president might nominate Attorney General Alberto Gonzales to the high court. They worry that the attorney general may not be conservative enough.

President Bush recently expressed unhappiness with conservative critics of Mr. Gonzales and urged the Senate, which must confirm his choice on the court, to ignore the appeals from both sides.

"I hope the United States Senate conducts themselves in a way that brings dignity to the process and that the senators do not listen to the special interest groups, particularly those on the extremes (extreme liberal and conservative groups)," Mr. Bush says.

Sen. Arlen Specter 
It will be up to the Senate to confirm the president's Supreme Court nominee. Senators from both parties are urging the special interest groups to cool their rhetoric. Among them is the Republican chairman of the Senate Judiciary Committee, Arlen Specter of Pennsylvania.

"I think that the word ought to go out that the special interest groups vastly overstate their influence, that what they are doing is counterproductive and a lot of time insulting," Mr. Specter says.

That may be hard to do given the political stakes involved in President Bush's first appointment to the high court in the wake of the Supreme Court's first vacancy since 1994.

Jonathan Turley is a veteran observer of the court and a professor at George Washington University Law School in Washington.

"Democrats view the Supreme Court as the last check on power in the United States. It is rare to have both houses of Congress and the White House controlled by the same party. Americans historically have preferred divided government. They prefer to have parties in control of different branches," Mr. Turley says.

Justice O'Connor was frequently the key vote in a series of five-to-four decisions handed down by the Supreme Court on a host of controversial issues including abortion, affirmative action, and the roles of the federal and state governments.

American University presidential historian Allan Lichtman says a philosophical shift on the high court would have enormous implications on a wide range of issues.

"Also at stake are issues regarding the separation of church and state, access by individuals to seek grievances redressed in court, interpretation of the environmental laws, interpretation of product liability laws. All of these things are critically at stake in the judiciary, which serves for life," Mr. Lichtman says.

Depending on their point of view, special interest groups will try to mobilize grass roots support either for or against the president's nominee.

But some analysts caution that those Washington-based interest groups may not always be speaking for large segments of the general public.

Thomas Keck is a political science professor at Syracuse University in New York.

"There are obviously some sharp political divisions among the American people as a whole. But the political scientists who have studied these issues in recent years have really been making a strong case that the political elites in Washington, D.C., are much more polarized, members of Congress are much more polarized than the American people as a whole," Mr. Keck says.

Once the president announces his choice for the high court, Senate Republicans say they hope to have a replacement for Justice O'Connor confirmed in time for the beginning of the next Supreme Court term in early October.