Court nomination fights have traditionally served to electrify each party's voter base, and the confirmation process to fill the seat of departing Justice John Paul Stevens will come as members of Congress are accelerating their reelection campaigns.  Since Obama nominated Judge Sonia Sotomayor to the court in June, the political climate has become far stormier, in no small part because of his effort to secure health-care reform legislation and Republicans' near-united stand against the president's proposals.  Many Republicans regard continuing opposition to Obama's agenda as their best hope to pick up seats in the November midterm elections, and Democrats are a vote short in the Senate of being able to avoid a filibuster that has been used only once in a Supreme Court nomination fight.  Meanwhile, the Sotomayor confirmation process has given the White House momentum heading into this one, including a short list of vetted candidates, and presidential aides are confident in their ability to successfully navigate the weeks ahead.  Their chief concern is how quickly the Senate will act; they fear that Republican delays could push the confirmation process past the August recess and fully into the fall campaign season.  "In a way, it's premature to say how this will unfold until we know who the nominee is going to be and what record they will bring to the process," said Robert Dallek, a presidential historian. "But the one thing I am sure of is that it won't be an appointment that flies through the Judiciary Committee and the Senate without some extremely contentious debate."  Bill Clinton was the last president to fill a Supreme Court seat in a midterm election year, in 1994, and his choice, Judge Stephen G. Breyer, was confirmed 87 to 9. After Obama nominated Sotomayor to replace retiring Justice David H. Souter, the Senate confirmed her by a vote of 68 to 31.  Neither of those nominations changed the liberal-conservative balance on the nine-member court, which often decides the most controversial issues by a single vote. Similarly, Obama will not be making a "balance-upsetting pick" in replacing Stevens, said a senior administration official, suggesting that the choice should inspire "less of a battle mentality" than if a conservative justice were retiring.  Administration officials say they are prepared to move faster than they did on the Sotomayor selection because many of the leading candidates have already been vetted, including three whom Obama interviewed as finalists.  "Obviously, it helps that we've been through the process once before," the official said, speaking on the condition of anonymity to discuss internal White House thinking. "We're not starting from scratch this time."  Obama nominated Sotomayor on June 1, and the Senate confirmed her by the August recess, despite delays that arose over her past remarks suggesting that, in some circumstances, Latinas make better judges than do white men.
No matter whom President Obama puts forward as his next Supreme Court nominee, the White House is anticipating a fight within the sharply divided Senate, one made even more fractious by election-year politics.