In this time of terrorism, the most important marks to be made by John Roberts and President Bush's next Supreme Court nominee on our law and society may not involve abortion, gay rights, women's rights, privacy, affirmative action, religion, or crime. Instead, they may involve claims by Bush, and perhaps his successors, of extraordinary powers as commander-in-chief—at home as well as abroad—to fight the war against terrorism.

Given the unsettled state of the law in this area, a Chief Justice Roberts and another Bush justice could play crucial roles in determining how strong a check the Court will provide on presidential moves to override civil liberties, international treaties, and congressional objections. And one critical question to be explored during Roberts's testimony next week is whether, as some experts fear and others hope, his record suggests an inclination to push for greater deference to the president.

These two vacancies come at a time when jihadists bent on mass murder—and eager to obtain nuclear or biological weapons—pose a domestic security threat graver than any we have faced since World War II, perhaps even since the Civil War.

There is a broad consensus that the magnitude of this threat requires a muscular presidential response and considerable judicial deference. But there is much disagreement about the need for, and the constitutional legitimacy of, some of the powers claimed by Bush and his advisers.

These claims are arguably more expansive than those of any other president since Franklin Roosevelt. They include the authority to detain, indefinitely and without trial, suspected "enemy combatants" seized in this country and around the globe; to subject them to brutally coercive interrogation methods; and to prosecute them in Bush-created "military commissions"—with possible penalties including death, with fewer protections than those enjoyed by defendants in ordinary military and civilian courts, and with no appeals outside the military chain of command.

The Supreme Court reined Bush in somewhat in two June 2004 decisions involving "enemy combatants," by votes of 8-1 and 6-3. "A state of war is not a blank check for the president when it comes to the rights of the nation's citizens," wrote Justice Sandra Day O'Connor for the plurality in the first case.

And even conservative firebrand Antonin Scalia—usually a champion of broad presidential powers—added, "The very core of liberty secured by our Anglo-Saxon system of separated powers has been freedom from indefinite imprisonment at the will of the executive."

Big Issues on the Horizon

But the administration interprets the June 2004 decisions quite narrowly. The rulings left many critical issues unresolved. Other cases involving suspected enemy combatants are working their way through lower federal courts. The jihadist threat is likely to stalk us for decades. And if administration forecasts of more massive attacks on America prove correct, a great many more cases like that of Jose Padilla may arise.

A U.S. citizen arrested in Chicago on suspicion of plotting a dirty-bomb attack, Padilla has been held in military brigs without criminal charges since 2002. He underwent more than two years of incommunicado interrogation with no access to a lawyer or to any court.

Might something similar happen someday—perhaps after an attack even more lethal than 9/11—to dozens, hundreds, even thousands of American citizens and others who fall under (perhaps misplaced) suspicion? Should something similar happen in the hope of preventing still more attacks?

Mass roundups and indefinite military detentions are at least theoretically possible under the administration's reading of the Constitution. Would a Roberts Court uphold them?

Some critics of Bush's detention policies express deep concern—based on hints gleaned from Roberts's two-year record as a judge on the U.S. Court of Appeals for the D.C. Circuit and his nine years of service in the Reagan and first Bush administrations—that he may be inclined to give Bush (or any president) something close to the "blank check" that O'Connor so pointedly ruled out.

(These critics are even more concerned about Attorney General Alberto Gonzales, a prime architect of Bush's legal claims who is also a leading contender to fill the second vacancy on the Court.)

Other experts, of a hawkish bent, hope that a Roberts Court will be more deferential to the president than O'Connor and her colleagues were in the 2004 decisions, which these experts see as unwarranted impediments to protecting the national security.

Still others contend that Roberts's record suggests no inclination to rubber-stamp presidential moves to override civil liberties or treaty obligations.

Judge Roberts's views on such issues will be one focus of questioning by Senate Judiciary Committee Democrats. Sen. Patrick Leahy of Vermont, the ranking Democrat, has served notice that he will grill the nominee about a now-inoperative August 2002 Bush Justice Department memo that (Leahy implied) puts the president "above the law."

This memo argued that the president has "complete authority over the conduct of war," including power to order the torture of prisoners (which the administration says it has never done), and to nullify (to that extent) treaties and a 1994 act of Congress that makes torture a crime.

The effort to divine the views of Roberts (who had no connection with the August 2002 memo) will also focus on a major war-on-terrorism case, Hamdan v. Rumsfeld. There Roberts joined two other judges in upholding, on July 15, the power of the special "military commissions" ordained by Bush in November 2001 to try suspected terrorists for war crimes.

Hamdan is worth a fairly detailed look for what it shows about Judge Roberts, about Bush's military commissions, and about the difficulty of some of the issues that the war on terrorism is forcing the judiciary to confront.

A Page of History

These issues are playing out against a rich historical background, from which different experts draw very different lessons.

The Constitution divides war powers between the executive and legislative branches, most obviously by making the president "commander-in-chief" of the armed forces while vesting in Congress the power to "declare war."

Less well known are the facts that the Constitution—while saying nothing more about the president's war powers—also grants Congress the powers to "make rules for the government and regulation of the land and naval forces"; to "define and punish piracies ... on the high seas, and offenses against the law of nations"; to "make rules concerning captures on land and water"; to "raise and support armies" and a Navy; and to provide forces to "suppress insurrections and repel invasions."

President George Washington said in 1793, "No offensive expedition of importance can be undertaken until after [Congress has] deliberated upon the subject, and authorized such a measure." Most other Framers of the Constitution, including James Madison and Chief Justice John Marshall, similarly emphasized the primacy of Congress in matters of war. In their view, presidents could act unilaterally only to repel "sudden attacks" that occur before Congress can respond.

In short, the Framers would have been most surprised to hear the view detailed in the August 2002 memo that they had given the president "complete authority over the conduct of war," and that this authority included indefinite detention of citizens without trial.

But ever since President Jefferson warred against the Barbary pirates, presidents have launched dozens of acts of war abroad without explicit congressional authorization. Recent examples include the Korean War, the surprise invasions of Grenada in 1983 and Panama in 1989, the occupation of Haiti in 1994, and the bombing of Kosovo and Serbia in 1999.

To some extent, such a unilateral presidential role abroad has become inevitable since World War II, with American forces ringing the globe and the threat of "sudden attacks" possibly involving nuclear-tipped missiles—or, now, nuclear truck bombs. Meanwhile, congressional passivity and deadlock have given presidents free rein to use military force on their own authority.

The Supreme Court has always avoided sitting in judgment of the legality of presidential acts of war overseas. But presidential actions on the home front are a different matter.

To be sure, the Court has sometimes bowed to vast presidential curtailments of civil liberties. The most infamous example is the 1944 decision upholding the detention of 110,000 Japanese-Americans—mostly U.S. citizens—in prison camps during World War II.

But that decision has been widely discredited. And in other cases, the justices have held that constitutional freedoms trumped presidential powers. Most relevant to Hamdan, in 1866, in Ex parte Milligan, the justices invalidated the trial by military commission of an Indiana resident for conspiring to overthrow the government and help the enemy.

Military trials of captured enemies on war-crimes charges had been used during the Revolutionary War (by General Washington), the War of 1812, the Mexican-American War, and other conflicts, as well as the Civil War. But Milligan held that "martial rule can never exist where the courts are open" and that the Constitution "is a law for rulers and people, equally in war and in peace, and covers with the shield of its protection all classes of men, at all times, and under all circumstances."

Bush's military commissions would have trouble passing this test, because both state and federal courts are very much open for business. But the continued validity of Milligan was clouded by the Court's 1942 decision in Ex parte Quirin, on which Bush has heavily relied.

Quirin unanimously upheld the trial by a presidentially created military commission and the subsequent execution of several German agents (including one U.S. citizen) who had confessed to sneaking into the country from German submarines with orders to blow up munitions plants, shopping areas, and the like. Such direct attacks upon civilians by enemy fighters under civilian cover—"unlawful combatants," in the Court's Quirin parlance—have long been treated as war crimes.

While the case was pending, President Roosevelt suggested to Attorney General Francis Biddle that he would defy any decision invalidating his military commission. Whether Biddle privately signaled this to the justices is unclear. But their unanimous decision—which several of them later regretted—drew an exceedingly fine distinction to hold Milligan inapplicable because the saboteurs were part of an enemy military force and Lamdin Milligan was not.

Between 1942 and 2001, Quirin had been all but forgotten. Meanwhile, Congress had provided defendants in military courts with most of the same protections afforded by state and federal courts. And the justices had become increasingly willing to strike down what they deemed to be presidential violations of constitutional liberties on the home front.

In 1952, for example, in Youngstown Sheet & Tube Co. v. Sawyer, the Court ruled unconstitutional President Truman's congressionally unauthorized seizure of the nation's steel mills, designed to prevent a labor dispute from impeding the war effort in Korea.

Bush on War Powers and the Court's Response

In claiming nearly absolute powers over suspected enemy combatants, at home as well as abroad, Bush has invoked both his own authority as commander-in-chief and the broad language of a September 18, 2001, congressional resolution. It authorized the president to "use all necessary and appropriate force" against nations, groups, and people that played any role in the 9/11 attacks or harbored those who did.

Bush and his advisers have also adopted an extremely narrow (and sometimes dismissive) interpretation of some treaties championed by past presidents. These include the 1949 Geneva Conventions and the U.N. Convention Against Torture and Other Cruel, Inhuman, or Degrading Treatment or Punishment. The Geneva Conventions bar (among other things) rough interrogation or treatment of prisoners of war. They also require (rather cursory) hearings before a "competent tribunal" to determine whether captives should be treated as POWs, as noncombatant civilians, or as unlawful combatants.

The Supreme Court has passed judgment on only three of the major issues raised by Bush's war-on-terror measures. In Hamdi v. Rumsfeld, a splintered 5-4 majority upheld Bush's power to detain without criminal charges or trial a U.S. citizen allegedly captured while he was with Taliban forces in Afghanistan. But it rebuffed by 8-1 Bush's claim that the man was entitled to no judicial hearing of any kind. Instead, O'Connor's opinion ordered that the detainee be given legal assistance and a chance to convince a "neutral decision maker" that he was not an enemy combatant.

In Rasul v. Bush, a 6-3 majority rejected the Bush position that federal courts have no power to hear petitions seeking the release of foreigners seized abroad as suspected enemy combatants and held at Bush's prison camp at the Guantanamo Bay Naval Base.

The Hamdi ruling did not specify what procedures must be used; how long a citizen-detainee could be held; or under what circumstances (if any) a citizen-detainee captured in this country could be militarily detained. (The justices dismissed an appeal by Padilla as having been filed in the wrong court.)

The even more cryptic Rasul opinion did not say what, if any, judicially enforceable rights Guantanamo detainees have, or whether federal courts can hear petitions seeking release of foreign detainees held by U.S. forces in other parts of the world.

And neither decision said whether Bush could put foreign detainees who are accused of war crimes—and who clearly could be prosecuted in ordinary military courts—on trial in his own military commissions.

This last question was the one answered in the affirmative by the three-judge D.C. Circuit panel in Hamdan, in a 20-page opinion written by Judge A. Raymond Randolph and joined by Judge Roberts and (for the most part) Judge Stephen Williams.

John Roberts and the Hamdan Case

Salim Ahmed Hamdan, a native of Yemen, has admitted to being Osama bin Laden's personal driver for several years. But he disputes the government's charge that he was part of bin Laden's broad conspiracy to murder civilians. His trial was put on hold when his lawyers filed a petition in U.S. District Court claiming that it would violate both the Constitution and the Geneva Conventions.

U.S. District Judge James Robertson upheld these claims in part. But on appeal, the D.C. Circuit panel rejected them and ruled that the military commissions could proceed. Citing Quirin and ignoring Milligan, Judge Randolph's opinion ruled that (1) the congressional authorization of "all necessary and appropriate force" and other laws had approved presidential creation of military commissions; (2) the Geneva Conventions are not judicially enforceable; and (3) even if they were, courts must defer to Bush's view (disputed by most legal experts) that these conventions are completely inapplicable to people captured in Afghanistan. Judge Williams disagreed with the third point, saying that the president's interpretation was clearly wrong.

(Some legal ethicists say that Roberts should have recused himself because he knew that he was under White House consideration for the Court while the case was pending.)

In a pending petition seeking review by the Supreme Court, Hamdan's lawyers sharply distinguished the power to punish suspected unlawful combatants for war crimes, as Bush's military commissions were created to do, from the power to detain them, which the petition concedes. It was prepared by Neal Katyal, a Georgetown law professor with a generally broad view of presidential power.

Katyal's petition rejects as "not plausible" the D.C. Circuit's holding that Congress's approval of "force" was meant to include unilateral executive branch trials and punishments far from the zone of combat. It says that the commissions' procedures change at the whim of the executive, load the dice in favor of the prosecution, and "flout basic tenets of military justice." It deplores as perhaps unprecedented in American history the exclusion of Hamdan from portions of his own trial lest he hear sensitive evidence. It argues that the Geneva Conventions can be invoked by a prisoner to challenge the legality of his detention, even if they are judicially unenforceable in other contexts.

By approving a presidentially created, all-executive-branch criminal process in a "war" with no identifiable enemy and no end in sight, argues the petition, the D.C. Circuit "vastly expanded presidential power" and "radically extended legal precedents."

Other experts dispute all of this. They contend that Hamdan "does not reflect an unusually broad view of presidential powers, falls far short of giving the president a 'blank check,' and was the most plausible reading of Quirin," in the words of Harvard law professor Jack Goldsmith. (He is a veteran of the Bush Justice Department and a friend of Katyal, who is a veteran of the Clinton Justice Department and who once wrote a letter supporting Roberts's nomination for the D.C. Circuit.)

Goldsmith also dismisses suggestions by others that Judge Roberts's years in the executive branch predispose him toward unusual deference to presidential power. Goldsmith cites as evidence opinions by other members of the Court who had been Justice Department officials, including Scalia, William Rehnquist, and former Attorney General Robert Jackson.

Judge Roberts has said that Jackson is one of the justices he most admires. Perhaps some senator will ask Roberts next week whether he shares the passion expressed in Jackson's concurrence in the 1952 Youngstown case:

"No penance would ever expiate the sin against free government of holding that a President can escape control of executive powers by law through assuming his military role."

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