SANDRA DAY O’CONNOR, the first woman appointed to the Supreme Court, resigned yesterday, igniting what promises to be one of the most explosive political fights in years over the legal and cultural direction of American life.

Ms O’Connor’s retirement, at the age of 75, creates the first vacancy on the nation’s highest court since 1994. It gives President Bush his first opportunity to reshape the court in line with his own conservative philosophy.

It also presages a potentially bitter struggle with Democrats and liberal groups, who have vowed to oppose any nominee they regard as too right-wing. The Senate must confirm Mr Bush’s nominee and, though Republicans have a majority, Democrats have enough votes to block any nomination through the filibuster. Mr Bush yesterday praised Ms O’Connor’s 24 years on the court but offered no clues as to the identity or approach of his likely nominee.

“I will select a Supreme Court justice that Americans can be proud of,” he said. The President, anticipating the possibly rancorous nature of the debate ahead, also called for a “dignified” confirmation process in the Senate, “characterised by a fair hearing and a fair vote”.

The retirement in fact poses Mr Bush with an acute dilemma, whose resolution will have significant ramifications both for his presidency and for the broader terms of legal and political debate in the country for years to come.

He could appoint a reliably conservative justice in line with most Republicans’ views on issues such as limiting abortion, outlawing euthanasia, opposing gay marriage and affirmative action. Among the names mentioned in this mould are current appeal court justices Michael Luttig and Emilio Garza; but that sort of nomination would provoke a bloody fight with Democrats and left-wing pressure groups.

Democrats have a long track record of opposing conservative nominees, whom they regard as likely to reverse the largely liberal direction that the court took in these areas in the 1960s and 1970s.

They rejected Ronald Reagan’s nomination of Robert Bork in 1987 and they fought hard to defeat Clarence Thomas in 1991. The Thomas hearings turned into some of the most extraordinary political theatre in modern times, with live nationally televised sessions focused on the African-American judge’s conservative views and alleged sexual harassment of a young legal assistant, Anita Hill. He was eventually confirmed by a narrow margin, but only after he had condemned the hearing as a “high-tech lynching”.

Mr Bush could avoid that sort of strife with a consensus figure, someone more acceptable to Democrats who would not depart significantly from the current court’s evenly balanced centrist approach. Alberto Gonzales, the current Attorney-General and a close friend of Mr Bush, would fit this bill. While on the Texas Supreme Court, for example, he opposed many efforts to place restrictions on abortion rights.

That would provoke outrage among the President’s conservative supporters. They have been chafing for a Supreme Court nominee more in tune with their view for 15 years. Before the battles of the late 1980s and 1990s, it had been widely accepted that an elected president had the right to have his nominees approved, unless they were far outside the mainstream of American life.

The O’Connor retirement makes Mr Bush’s dilemma especially acute because she has often been the swing voter on the nine-member court over the past two decades.

Ms O’Connor was appointed in 1981 by President Reagan, and though she arrived with strong conservative credentials she quickly proved herself to be right in the centre of the court’s political spectrum. She has upheld abortion rights, with minor modifications, has validated the principle of affirmative action but restricted its operation, and supported the death penalty while imposing limits on its application.

“We want someone exactly in the O’Connor mould,” said Elliot Mincberg, of People for The American Way, a liberal pressure group.

It had been expected that Chief Justice William Rehnquist, a more reliably conservative member of the court, would be the one to retire this summer. He has thyroid cancer and is evidently gravely ill; but by letting Justice O’Connor go first, the Chief Justice has brought the more difficult nomination process first, perhaps allowing Mr Bush an easier ride when Mr Rehnquist retires.

Yesterday’s news fired the starting gun for a campaign that will have all the hallmarks of a national election. Political groups on left and right have raised millions and prepared war rooms in readiness.

When Mr Bush announces his nominee, they will launch television advertising campaigns, large public protests and intense lobbying efforts on members of the Senate. Yet for all the intensity of the fight, it is not always easy to be sure how a Supreme Court nominee will act when they reach the court. David Souter, appointed in 1990 by President Bush’s father, who took him to be a fellow conservative, has proved to be one of the court’s most left-wing members.

Dwight Eisenhower, the Republican President, appointed Earl Warren as Chief Justice and William Brennan as Associate Justice. Both proved crucial in driving the court into one of the most liberal phases in its history in the 1960s. Years later President Eisenhower remarked: “I only made two mistakes in my presidency. And they’re both sitting on the Supreme Court.”

OLD GUARD

Stephen Breyer, 66. Appointed by Clinton in 1994. Liberal

CONTENDERS

Emilio Garza, 58: former Marine captain; Texas trial judge. Would be first Hispanic appointment since 1930s

Michael McConnell, 50: former law professor at the Universities of Chicago and Utah

J. Harvie Wilkinson, 60: Justice Department official under Reagan

Samuel Alito, 55. Former deputy assistant attorney general under Reagan

Times Recommends

• The lives of the Lehman ladies
• The training school for teenage Taleban