Will George W. Bush nominate a conservative or a moderate to replace Justice Sandra Day O’Connor? Will he name his friend Attorney General Alberto Gonzales? Will he move with dispatch, or draw out his deliberations in order to shorten the window available for a contentious nomination? Instead of holding our collective breath, we should use this pause between O’Connor’s resignation and Bush’s nomination of a successor to pose one eminently answerable question in a different direction entirely: to Senate Democrats. Will the future of the Supreme Court inspire greater unity than the war on Iraq, greater energy than tax cuts for the wealthy, more nerve than the recent compromise over lower-court filibusters? How those Democratic senators–most of whom have never faced a Supreme Court nomination–reply may well define their careers.

The legal consequences of replacing O’Connor with a more rigid ideologue are easy enough to predict. A New Hampshire abortion-rights case concerning parental notification is on the docket for the fall, and cases on campaign finance, the environment, criminal justice–all areas in which O’Connor in recent years demonstrated flexibility and pragmatism, and all critical to Democratic constituencies and interests–are not far behind.

This already commenced confirmation battle is not only about an as-yet-unknown O’Connor replacement but also about setting the terms and atmosphere for inevitable Bush nominations to come. (As of this writing, Chief Justice William Rehnquist, suffering from thyroid cancer, is again in the hospital.) And how this plays out may well shape the entire Supreme Court’s understanding of the country’s social consensus.

Conventional wisdom holds that the Supreme Court is above politics. But when three Reagan/Bush nominees–O’Connor, Anthony Kennedy and David Souter–completed the unfinished reproductive-rights revolution with Planned Parenthood v. Casey in 1992, they made it clear that political consensus was precisely the point. In their plurality opinion, O’Connor, Kennedy and Souter warned of “profound and unnecessary damage to the Court’s legitimacy” should abortion rights be abolished. When they wrote that “the ability of women to participate equally in the economic and social life of the Nation has been facilitated by their ability to control their reproductive lives,” they were not just enhancing the legitimacy of Roe v. Wade but reflecting a generation of Congressional debate over women’s rights–debate that included the galvanizing argument over sexual harassment surrounding the Clarence Thomas hearings before an all-male Judiciary Committee.

This is why the unity of Democratic, civil rights and public-interest constituencies in the coming weeks is so crucial. Senators and grassroots activists need to remember how the first President Bush effectively divided civil rights groups with the Thomas nomination. The NAACP and some influential African-American leaders, seduced by Thomas’s exaggerated rags-to-robes biography and reluctant to oppose a black nominee, initially closed their eyes to the consistency and ideological extremity of Thomas’s writings, allegiances and decisions, as well as to evidence of personal misrepresentations and ethical lapses. This time there can be no sentimental presumption that once a nominee is on the Court, ethnic identity or gender will trump a well-established track record on the far right.

What does this mean for any individual Democratic senator? Senators might reflect on whether Joseph Lieberman would ever have been nominated for Vice President if in 1991 he had followed through on his inclination to vote in favor of Clarence Thomas despite Anita Hill’s allegations of sexual harassment, instead of wisely attending to women on his staff and in his family who warned him of the cost.

Democrats also need to understand how deeply the Terry Schiavo case alienated mainstream America from the religious right–and the deep rift over the Court within the Bush coalition of social conservatives and corporate interests.

Where do the Democrats stand as President Bush makes his choice? Senate minority leader Harry Reid and Judiciary chairman Patrick Leahy called on Bush with suggestions of “consensus” nominees. That’s an unlikely prospect from this most consistent of Presidents. In the recent filibuster battle over lower-court nominees, seven Democrats chose the pragmatic preservation of their senatorial prerogatives over pushing the Priscilla Owen and Janice Rogers Brown nominations to a test. But in the matter of a replacement for O’Connor, the stakes are higher than with any Supreme Court nomination in history. To Democrats in the Senate–including risk-averse presidential aspirants like Joe Biden, Hillary Clinton, John Kerry and Evan Bayh–here is the message: This will be a legacy vote.