On July 15, the day President Bush interviewed John G. Roberts Jr. about an appointment to the Supreme Court, the judge was part of an appeals court panel that approved broad presidential powers in the war on terrorism.
The ruling gave the administration a green light to use military tribunals to try those labeled "enemy combatants" at the U.S. base at Guantanamo Bay, Cuba. And it said that those combatants had no right in U.S. courts to enforce provisions of the Geneva Convention on the treatment of prisoners of war.
"No decision, by any court in the wake of the Sept. 11, 2001, attacks has gone this far," said Neal K. Katyal, a Georgetown University law professor and attorney for one of the alleged enemy combatants, Salim Ahmed Hamdan, a Yemeni accused of being Osama bin Laden's driver and bodyguard.
How much power the president should have to detain people like Hamdan is among the hottest issues in American law. But it has received little attention so far in the debate over Roberts' nomination. That does not surprise those who have studied past confirmation battles.
Like generals, senators often fight the last war, focusing on the issues of previous decades, not those of the future, said Michael Comiskey, a political scientist at Pennsylvania State University and an expert on the history of Supreme Court nomination battles.
He noted that President Nixon successfully nominated four justices to the high court between 1969 and 1971. "No senator asked any of them a question about abortion," Comiskey said. In 1973, the Supreme Court decided Roe vs. Wade, declaring that the Constitution gives a woman a right to end her pregnancy.
Today, the debate over Roberts has focused on the generation-long fight that the Roe decision kicked off. But many legal experts on the left and the right, as well as political scientists and activists, believe that executive power could be the area in which a Justice Roberts would have the biggest impact.
The reasons involve Roberts' background -- a lawyer for the White House and the Justice Department -- and the fact that the nation is engaged in what may be a prolonged war on terrorism that is expanding the boundaries of the president's power.
"I think it's crucially important," said Neil Kinkopf, a liberal law professor at Georgia State University in Atlanta who worked in the Clinton administration. "There is no more important issue on the court's docket over the next few years than this one."
John C. Yoo, a conservative law professor at UC Berkeley, who has worked in the Bush administration and advocates enhanced presidential power, agreed.
"It's inevitable" that the court "will be confronted with a whole series of questions on foreign relations law and international law that would have been beyond the imagination of people in 1981" when retiring Justice Sandra Day O'Connor was appointed, Yoo said.
He predicted that the wars on terrorism and in Iraq -- as well as the Patriot Act -- would generate cases that would prove more difficult for the high court than those spawned by past wars.
"They will be even harder because the war is so different since Al Qaeda is not a nation," Yoo said. "There are no precedents."
The Bush administration has made extensive claims of presidential authority in the fight against terrorism, and so far has had mixed success in the courts. The biggest setback for the administration came in an opinion by O'Connor last year that rejected the argument that the president had unchecked power to imprison enemy combatants.
"We have long since made clear that a state of war is not a blank check for the president when it comes to the rights of the nation's citizens," O'Connor wrote. Even during wartime, the Constitution "assuredly envisions a role for all three branches [of government] when individual liberties are at stake."
The proper balance among those branches has been debated in the courts throughout the nation's history. During wartime, courts have tended to give the president considerable latitude, based on the assumption that he had superior knowledge of military needs.
Chief Justice William H. Rehnquist, for whom Roberts clerked after graduating from Harvard Law School, wrote a book on the subject titled "All the Laws but One: Civil Liberties in Wartime," in which he quoted an old Latin maxim: Inter arma silent leges -- in times of war, the laws are silent.
Based on material made public thus far, Roberts does not have a long paper trail on the issue of executive power. Legal experts, particularly those who are dubious of broad presidential claims to authority, have urged senators to ask him questions about his views on Supreme Court precedents.
But both sides in the debate over presidential power predict that because Roberts served eight years in the executive branch, he probably will sympathize with presidential claims of authority.