"An O'Connor resignation was not one we took seriously," Mr. Gray said, rushing out the door to begin deploying his troops.
At the abortion rights group Naral Pro-Choice America, organizers were sending e-mail alerts to 800,000 activists within 15 minutes after the announcement of Justice Sandra Day O'Connor's resignation. "Don't let Bush take away your choice!" they declared.
On Capitol Hill, senators of both parties quickly made their way to the floor and the galleries for a morning of speeches and briefings, hailing Justice O'Connor and trying to frame the debate to come - Democrats stressing a need for consultation and consensus, Republicans emphasizing a need for a fair process.
By midday, nothing less than a national political campaign had begun.
The retirement of Justice O'Connor, a moderate who has been a crucial vote for a constitutional right to abortion, began a struggle with incalculable political implications - for the interest groups, for the parties and for the president.
"This is the pivotal appointment," said Senator Dianne Feinstein, a California Democrat who sits on the Senate Judiciary Committee.
Advocates on the left and the right, who had prepared for this moment since the last Supreme Court vacancy was filled 11 years ago, agreed that the ideological balance of the court was up for grabs. Advocacy groups bought advertising on television and the Internet, and issued millions of e-mail alerts, waves of direct-mail fund-raising appeals and pre-emptive blasts at those viewed by the groups as either obstructionist Democrats or extremist Republicans.
"This is one of those moments in American history," said Ralph G. Neas, president of the liberal People for the American Way. "No matter what side you're on, everything you've believed in, everything you've cared about, everything you've fought for is at stake. It's such a closely divided court."
Social conservatives saw a chance finally to translate their political successes - the election of allies to the White House and the top of the Congress - into greater influence on the court. They immediately reminded Mr. Bush of his campaign promise to appoint judges in the mold of Justices Antonin Scalia and Clarence Thomas. They roused the grass roots, reminding their constituents of the court's decisions on the display of the Ten Commandments in public places, on gay rights and, most of all, on abortion.
"Today marks a watershed moment in American history," declared Dr. James C. Dobson, founder and chairman of the conservative Focus on the Family, "the resignation of a swing-vote justice on the Supreme Court and the opportunity to change the court's direction."
Lest there be any doubt about the high expectations of religious conservatives, Dr. Richard Land, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention, declared, "For President Bush, social conservatives and the senators they helped elect, the moment of truth has arrived."
Liberal advocacy groups found themselves confronting what they had feared and warned about since the 2000 election: the prospect of a Bush court. They called on the president to nominate a consensus moderate, someone ideologically and judicially close to Justice O'Connor. But they were preparing for something else.
Nancy Keenan, president of Naral, asserted that there could be no "stealth candidates" - that any nominee must be asked for a position on Roe v. Wade, the 1973 decision declaring a constitutional right to abortion, and that any nominee must answer.
Notwithstanding much of the rhetoric, Justice O'Connor's retirement will not end the court's majority for Roe, which stands at 6 to 3.
But her successor could narrow that majority, and open the door to new abortion restrictions. For example, the Supreme Court ruled by only 5 to 4 that a "partial birth abortion" ban was unconstitutional; Justice O'Connor's vote was among the five in the majority.
Another version of that ban, which applies to a type of abortion performed in the second or third trimester, is being challenged in lower courts and may end up before the justices.
Justice O'Connor's successor could change the balance on other issues as well, among them affirmative action and legislative redistricting. But it is abortion that will drive many activists in this nomination struggle.
A recent poll by the Pew Research Center found that dissatisfaction with the Supreme Court among Republicans was closely tied to their views about Roe v. Wade; those who want to see the decision overturned are twice as likely to give the court an unfavorable rating.
Nothing mobilized the modern religious conservative movement more than Roe, said John C. Green, an expert on religion and politics at the University of Akron.
"If you talk about judicial tyranny with any of the Christian conservatives, Roe v. Wade comes up immediately," Dr. Green said. "Some will talk about school prayer, but that was a long time ago."
The issue has a painful history for many opponents of abortion, who have felt betrayed by the string of Republican appointees, including Justices O'Connor, David H. Souter and Anthony M. Kennedy, who have ruled for abortion rights. Indeed, while much of Washington was awash in praise for Justice O'Connor on Friday, Carol Tobias, political director of the National Right to Life Committee, said in an interview that "Justice O'Connor has not been good for unborn children, so we do see any change as being positive."
Abortion rights groups are hopeful that the coming struggle will re-energize their supporters. They note that the last great surge of abortion rights activism occurred in the early 1990's, when it appeared that the court might be moving to overturn abortion's constitutional protections.
Most Americans support legalized abortion, polls show, though many would also like to see more restrictions on it. "This will take the issue back to the fundamentals," said Celinda Lake, a Democratic pollster who works for Naral.
This struggle over fundamentals - another battle in the culture wars - poses challenges for both parties. Many Democrats have tried to moderate their party's image in recent months, especially on values-related issues like abortion. Many Republicans, meanwhile, have tried to return to bread-and-butter economic issues, worried about polls showing that large numbers of voters see the party as out of touch with their concerns, after months dominated by fights over judicial filibusters.
But this judicial campaign will not be stopped, all sides agree, and there is a sense of foreboding about it.
"This is enormous," said Senator Feinstein, one of many trying to adjust to retirement by Justice O'Connor rather than Chief Justice William H. Rehnquist. "It's different from Rehnquist. It is enormous."