To fill the O'Connor seat, Bush first chose his White House counsel, Harriet Miers. A firestorm erupted amongst his own party as conservatives questioned both her views on key issues and her overall fitness for the post. The nomination was withdrawn three weeks after it was offered. Weeks later, Bush turned to an appeals court justice from New Jersey, Samuel Alito. Democrats pressed ahead for a fight they had been unable to wage against Roberts. Two dozen senators -- including Obama -- voted to filibuster the choice. But he ultimately won confirmation, by a vote of 58-42.

Bush's father, George H. W. Bush, saw his first pick for the bench, David Souter, win easy confirmation in October 1990 with 90 votes in the Senate. But his second attempt to fill a vacancy led to what longtime Supreme Court reporter Jan Crawford Greenburg called "one of the most lurid and personally explosive confirmation battles in Court history." The choice of conservative Clarence Thomas to replace liberal Thurgood Marshall alone created a tense atmosphere, but the emergence of allegations of sexual harassment from Anita Hill, a former aide. He ultimately won confirmation by a 52-48 margin.

President Reagan made history with his first Supreme Court choice, selecting a woman, Sandra Day O'Connor. She was confirmed without a single dissenting vote in September 1981. His second chance for a nomination would not come for another five years, when Chief Justice Warren Burger announced his retirement. Antonin Scalia is today one of the more controversial conservative members on the bench, but his confirmation was, like O'Connor's, unanimous.

But four days before that nomination was officially made, Reagan moved to elevate Rehnquist, then an associate justice, to be chief. Though he had been confirmed by a margin of 42 votes 15 years earlier, Democrats and liberal groups focused their energies on defeating the bid for a promotion. Crawford, in her 2005 book, "Supreme Conflict," says Rehnquist's nomination for chief justice "attracted the strongest recorded opposition in the history of the Senate for a chief justice," while Scalia's nomination "slid unnoticed under the radar." Reagan's third and final opportunity to fill a Supreme Court vacancy proved even more challenging, including the failed nomination of Robert Bork.

The recent exception for second nominations is Bill Clinton. His young presidency faced many setbacks, but his first- and only picks for the high court breezed to confirmation. Stephen Breyer was seated with just nine dissenting votes, a year after Ruth Bader Ginsburg had been confirmed by a vote of 96-3.

Obama now appears on the precipice of having his second chance to nominate a new justice. It's not uncommon for new presidents to have these opportunities so soon in a term, especially given that justices of a certain ideology are inclined to wait until a likeminded president takes office with the power to replace them. But Obama's second choice is complicated by a decline in personal popularity, the considerable political capital he expended in the health care fight, and the changed dynamic of the Senate since the election of Scott Brown in January. Republicans are now armed with a 41st vote that can sustain a filibuster. And such a filibuster could be likely as the party seeks to motivate its base heading into midterm elections.

Though a fight will likely materialize no matter who Obama chooses, the nature of that battle will of course be largely determined by the profile of the nominee. In choosing Sotomayor last year, Obama chose what some felt was a tougher road, ignoring potentially safer selections. Perhaps aware that his fortunes could change, a safer choice now may be his best hope to avoid the fate of some of his predecessors.