The next president - whether it is George W. Bush or John Kerry - will probably have an opportunity to shift the balance of power on the US Supreme Court in a way that could hold for decades.
With a long list of 5-to-4 decisions on hot-button issues like affirmative action, school vouchers, gay rights, and abortion, even a single appointment could prove decisive in some of the nation's most contentious legal disputes.
So it is not surprising that special-interest groups on both the left and right are alarmed at the prospect that a justice friendly to their cause could be replaced with a hostile jurist.
As a presidential campaign election issue, however, the Supreme Court has yet to emerge as a top concern of most voters. That is partly because the issue depends on three key events, none of which has occurred. There is no indication a justice will leave the court anytime soon. Thus, no replacement has been nominated. And since no replacement has been nominated, it is not possible to know whether there will be significant opposition to the nominee in the Senate.
But all that could change in an instant. And if partisan squabbles over President Bush's appointments to lower courts during the past four years are any indication, the next vacancy at the US Supreme Court could plunge the White House and Senate into a bitter, high-stakes battle.
While longtime court watchers acknowledge that possibility, many say the political realities of Washington may dictate a more restrained nomination scenario.
"Absent some significant change in the membership of the Senate," says David Garrow, a Supreme Court historian at Emory University in Atlanta, neither of these presidential candidates has any alternative "but to nominate within a fairly narrow window of moderation."
"No Republican expects Kerry to appoint a Republican, and no Democrat expects Bush to appoint a Democrat. But I think there is the expectation that if you want to get your people confirmed, they have to be judicial," says Sheldon Goldman, a political science professor at the University of Massachusetts at Amherst. "They can't be seen as advocates for the left or the right."
What this would mean in a Kerry administration is nominees similar to those named by President Clinton - Ruth Bader Ginsburg and Stephen Breyer. Two issues would probably frame the selection of moderate Democrat nominees by Senator Kerry - support of abortion rights and an indication that the US Constitution does not include a right to same-sex marriage, analysts say.
It remains unclear whether Bush would pursue a similar strategy aimed at placing Republican moderates on the high court - for example, someone similar to Sandra Day O'Connor, a Reagan appointee who has helped uphold abortion rights but who generally votes with conservatives on federalism issues.
Some analysts say the focus should be on the qualities of the individual nominee, rather than on political labels.
"I don't believe the only people who could get confirmed in a Senate controlled by Republicans, after all, are those whom the left is willing to describe as moderate," says Brad Berenson, a Washington lawyer and former associate White House counsel to Bush. "A conservative president is entitled to appoint a conservative justice if his nominee is well qualified and fair-minded."
Mr. Berenson adds, "There are certainly plenty of conservative jurists who fall into that category."
Bush has said he favors judicial candidates in the mold of Justices Antonin Scalia and Clarence Thomas. Both are strong conservatives, and both do not recognize abortion as a fundamental right. Senate Democrats suggest any nominees resembling Justices Scalia and Thomas will be blocked.
While Republican senators largely approved Justices Ginsburg (97 to 3) and Breyer (87 to 9), both of whom shared Mr. Clinton's abortion-rights outlook, it appears Senate Democrats are prepared to block any high-court nominee who they suspect may share Bush's antiabortion outlook.
Thus, if Bush is reelected, the stage appears set for a showdown.
Democratic leaders in the Senate have launched 10 filibusters to block Bush's nominees to federal appeals courts. The Democrats charge that the stalled nominees are conservative extremists outside the legal mainstream. The White House and Senate Republicans dispute such characterizations, saying that each nominee would win confirmation if given an up or down vote by the full Senate.
The Republicans have been unable to assemble the 60 votes necessary to end the filibusters, but they aren't without options. In two instances earlier this year, the White House circumvented filibusters by using "recess appointments" - appointments that happen when Congress is not in session - to place Alabama Attorney General William Pryor and Mississippi Judge Charles Pickering on federal appeals courts.
What remains unclear is whether Senate Democrats would resort to a filibuster against a Supreme Court nominee and whether the White House would respond by making a recess appointment to the high court as a means of forcing an up or down Senate floor vote.
"A vacancy cannot go unfilled indefinitely. And if the Senate refuses to vote up or down on a nominee, a recess appointment may be the only option a president has," says James Swanson, a senior legal scholar at the Heritage Foundation in Washington.
President Eisenhower used recess appointments to immediately place his nominees on the Supreme Court prior to Senate confirmation. All three - Earl Warren, William Brennan, and Potter Stewart - were later easily confirmed. But that was 50 years ago, and Eisenhower was acting in the interest of efficiency at the high court rather than in an attempt to bypass any Senate opponents.
In the current combative atmosphere in Washington, filibusters and recess appointments could trigger a kind of nominee Armageddon.
"I call this process constitutional hardball," says Mark Tushnet, a law professor at Georgetown University Law Center in Washington.
"If the scenario goes through to the point of a recess appointment, I don't think we have any idea what politics after that would look like," Professor Tushnet says. "It would be politics as war. Every issue would be a to-the-death issue."
Regardless of tactics and strategy, there is another factor that could play a key role in the future makeup of the high court. Sometimes it is impossible to predict how an individual will vote once he or she becomes a life-tenured justice.
"Any White House ought to appreciate that a president's predictive batting average for Supreme Court nominees historically never gets above .500," says Professor Garrow.
Of the five justices appointed by President Reagan and the first President Bush, three - Justices O'Connor, Anthony Kennedy, and David Souter - voted to uphold the Roe v. Wade abortion precedent. Indeed, all but two of the Supreme Court's nine justices were appointed by Republican presidents, but the court continues to issue decisions that are neither consistently conservative nor consistently liberal.
• For George W. Bush, the buzz about potential nominees includes J. Harvie Wilkinson and Michael Luttig, both federal appeals court judges on the Fourth Circuit in Virginia; Emilio Garza, an appeals court judge on the Fifth Circuit in Texas; and Samuel Alito, a Third Circuit appeals court judge in New Jersey. Also mentioned are White House Counsel Alberto Gonzales and Utah Sen. Orrin Hatch.
• For John Kerry, speculation is that he might tap Sonia Sotomayor, a Second Circuit appeals court judge in New York. Also mentioned are David Tatel and Merrick Garland, both federal appeals court judges on the D.C. Circuit in Washington; Sandra Lynch, a First Circuit appeals court judge in Boston; and Walter Dellinger, a Duke University law professor and acting solicitor general in the Clinton administration.
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