Liberals fear him. Conservatives distrust him. But all eyes will be on Kennedy as the court opens its 2007-08 term Monday with a string of major cases on the horizon that appear headed for 4-to-4 deadlocks.
Among them is a dispute over gun rights in Washington, D.C., a battle over the legal rights of terror suspects at the Guantánamo detention center, and a challenge to the president's power to order state judges to uphold international court rulings.
In addition, the high court will examine whether execution by lethal injection in Kentucky is a form of cruel and unusual punishment, and whether the Constitution forbids Indiana from requiring voters to produce photo identification prior to casting a ballot.
The same internal dynamics among the justices that produced a string of conservative victories on abortion, affirmative action, and campaign finance last term will again be on full display. But this term, Kennedy's positions on pending cases are less clear.
Some analysts say the highest-profile cases this year are likely to bring a broader mix of both liberal and conservative victories. But several of the cases appear too close to call, court watchers say.
One of the most anticipated cases involves a landmark legal dispute over the meaning of the Second Amendment right to keep and bear arms. The justices are being asked to decide whether this is an individual right that belongs to the people or a collective right bestowed by the states through organized militias.
The court has not yet agreed to take up the issue, but many constitutional scholars believe it soon will. If so, it would mark the first time since 1939 that the Supreme Court has examined the meaning of the Second Amendment.
Two related cases, District of Columbia v. Heller (07-290) and Parker v. District of Columbia (07-335), involve challenges to gun-control laws in the nation's capital. The disputes will take the justices back to the drafting of the Bill of Rights and the foundations of the republic, analysts say.
"This is 1791 for the Second Amendment," Georgetown Law Center Prof. Nicholas Rosenkranz told a recent conference at the Cato Institute in Washington.
Among cases already on the court's docket, one of the most important involves terror suspects at Guantánamo Bay and to what extent they are entitled to challenge their open-ended detention as enemy combatants.
Lawyers for the detainees filed habeas corpus petitions asking federal judges in Washington to examine the legality of their clients' continued confinement. The Bush administration says that because the detainees are foreign enemy combatants being held outside the United States, they are not entitled to the protections of habeas corpus. In 2006 Congress, then controlled by Republicans, passed a law that stripped federal judges of jurisdiction to hear cases brought on behalf of detainees at Guantánamo.
When lawyers for the detainees first asked the Supreme Court to take up the issue, the justices refused. Then, in a highly unusual move, the justices agreed three months later to hear the appeal. This has led to speculation that the court is primed to overturn an earlier federal appeals court ruling upholding the Bush administration's position and the 2006 law.
Some analysts go even further. "The court took this case to make a larger statement of who we are as a people," says Neal Katyal, a law professor at Georgetown Law Center, who also represents a Guantánamo detainee in a pending case.
Professor Katyal, speaking on a recent panel at Georgetown, said the court will probably rule that fundamental rights apply at Guantánamo. "I expect a broader holding than we have had in the past," he added.
Supporters of the Bush administration say the court is unlikely to take such a dramatic step – even six years after the 9/11 attacks. The US is still at war, they say.