Barack Obama has taken the presidential oath of office at a time of bitter war and economic crisis. He promised to meet the many challenges facing America, but within our tradition of constitutional liberty: "we reject as false the choice between our safety and our ideals," he told the nation in his inaugural address. Those ideals require an impartial investigation and the potential prosecution of anyone in the Bush administration who may have violated the law.

As Gerald Ford commented after taking over from Richard Nixon, "our long national nightmare is over." Without question, President George W. Bush did what he thought was right, but much of it was wrong. He was wrong to take America into an unnecessary war. He was wrong to build a foreign policy on hubris. He was wrong to sacrifice civil liberties for the appearance of security. He was wrong to demonize his political opponents. He was wrong to fill government positions with partisans and cronies. He was wrong to inflate executive power. He was wrong to break America’s budget. He was wrong to add trillions of dollars in liabilities to the nation’s entitlement crisis. He was wrong to spread bailouts far and wide. He was wrong to centralize power in Washington. He was wrong on many matters of policy, big and small.

For all of these he deserves to be exiled to the far reaches of the American political system. No favored status as elder statesman. No keynote addresses at important political or economic conferences. No respected appearances in print or on screen. Let The Decider leave the rest of us alone as we struggle with the disastrous consequences of eight years of his administration’s arrogance, ignorance, and incompetence.

For none of these errors does he deserve to be prosecuted, however. No matter how bitter our policy and political disagreements, they should never be treated as crimes. One of the majestic aspects of genuine liberal democracy is that no matter how messy, disappointing, petty, foolish, and perverse the process, power transfers peacefully and the losers can proceed about their lives unmolested by the victors. Enter a business, write a book, join a think tank, promote a charity, give a speech, or become a hermit: all possibilities are open to the former "most powerful person on earth."

But not all presidential errors are merely questions of policy or politics. Some are matters of the law. The criminal law.

Contrary to Richard Nixon’s axiom, the fact that "the president does it" does not mean that "it is not illegal." One of the other grand characteristics of a liberal democratic society is that even those with power, wealth, and influence are bound by the law. The system might not always work well, let alone as well as we desire. But political office provides no immunity for criminal acts.

So it should be with President Bush and his appointees. The question is not whether they believed they had the power or that their actions were necessary to protect America. The question is whether they actually had the power under the law of the land, both Constitution and statute.

Not all areas of dubious conduct are criminal. The administration behaved irresponsibly in manipulating intelligence regarding Iraq, but believing what one wants to believe is different from knowingly falsifying evidence. The congressional authorization of war with Iraq may have been inadequate, since Congress should make the decision and not delegate responsibility to the executive branch. However, it hardly seems appropriate to prosecute a president for taking advantage of Congress’ express abdication of its constitutional obligations. Other misbehavior, such as contempt of Congress, has satisfactory remedies, most obviously congressional enforcement through judicial action and retaliation by cutting executive appropriations and taking other punitive measures.

Similarly, the president and his aides continuously made extravagant claims of executive authority regarding the power to arrest, imprison, and try enemy combatants. However, the president complied with court rulings when challenged and, again, was aided and abetted by a compliant Congress. The role and rules of military commissions were sorted out by a complicated  and admittedly unsatisfying  mix of presidential claims, court cases, and congressional legislation. Nevertheless, the differences were properly left to politics, not prosecutors. In these and other cases, Congress should use its full powers to investigate, perhaps creating special joint investigative committees and/or an independent commission, but the Justice Department should not prosecute.

Not every disagreement can be so brushed aside, however. The destruction of CIA tapes of interrogation sessions could be obstruction of justice, for instance. In two other areas, in particular, the administration appeared to flagrantly violate the law. First, the administration violated the Foreign Intelligence Surveillance Act (FISA), which set legal standards for wiretapping American citizens in national security cases. Second, the administration violated legal prohibitions on the use of torture (and cruel and inhuman treatment). Violations of both laws are felonies.

President Barack Obama would appear to agree, though he has been an inconsistent advocate of civil liberties. He denounced the Bush administration for violating the FISA statute, but voted for a weak compromise that gave that administration most of what it wanted. He is preparing to sign an executive order to close Guantánamo Bay, his CIA Director-designate, Leon Panetta, has criticized torture, and his Attorney General-designate Eric Holder acknowledged that water-boarding is torture. But at his confirmation hearing Holder also appeared to endorse preventive detention and warrantless surveillance.

What to do about the Bush administration’s putative law-breaking? Last April candidate Obama asserted that "If crimes have been committed, they should be investigated." However, he added that "I would not want my first term consumed by what was perceived on the part of Republicans as a partisan witch hunt." Before taking office in January he said "I don’t believe that anybody is above the law. On the other hand I also have a belief that we need to look forward as opposed to looking backwards." Moreover, at his confirmation hearing Eric Holder backed away from his assertion last year that "we owe the American people a reckoning," saying he meant "information-sharing" rather than prosecuting. Yet one aspect of the president’s duty to faithfully execute the law is to hold accountable federal officials, whoever they may be, who fail to do so.

Both areas require investigation, certainly, reform, undoubtedly, and prosecution, possibly. President Obama should appoint an independent prosecutor, to avoid fears of partisan retribution, to detail what administration officials did, assess the legality of their conduct, consider any factors mitigating illegal behavior, and bring any appropriate indictments. Then the president and Congress should take executive and legislative steps to prevent any recurrence.

Presumably the Bush administration believed that it was acting legally. Genuine belief by officials that their conduct was legal might militate against prosecution, but alone should not be enough to insulate illegal and unconstitutional behavior. High government officials must be held accountable for their actions. Otherwise future officials will realize that they can violate the law with impunity by simply claiming that they believed the law to on their side.

In the case of FISA, administration officials and advocates such as Vice President Richard Cheney appeared to act on behalf of what could be called the Regal Presidency  the theory that the Constitution really created an elective king rather than a republican chief executive. They buttressed this position by claiming that the Authorization for Use of Military Force repealed any and all statutes which the president viewed as impeding his war power, even though no one in Congress bothered to mention this possibility when voting for the bill.

In this view, the president’s job is to make policy, run the government, and order around the rest of us. Congress’ role is to pass whatever legislation the president desires. The courts are supposed to approve whatever the executive does. It’s an interesting theory, but utterly disconnected from the nation’s political tradition, the intent of the Founding Fathers, and the will of the early Americans who only reluctantly ratified the Constitution, fearing that it created too strong a federal government, and especially chief executive. On this issue Alexander Hamilton, who actually proposed a Regal Presidency, lost, decisively, at the Constitutional Convention. (Ironically, the result of Bush administration overreaching has been to embolden the judicial and legislative branches, helping to limit power that President Bush viewed as essentially limitless.)

The more serious argument is simply that the president, as military commander-in-chief, has uniquely expansive authority in military matters. His role in this area requires more than the usual power and discretion. Which means that if he believes surveillance to be necessary to protect America’s national security, then he has the authority to act, irrespective of the language of the Constitution or statute. The 2002 memo written by John Yoo, then deputy in the Office of Legal Counsel, asserted: "the president enjoys complete discretion in the exercise of his Commander-in-Chief authority and in conducting operations against hostile forces." (Notably, at the time both Attorney General John Ashcroft and Deputy Attorney General James Comey resisted this interpretation, at least when it came to FISA.)

Undoubtedly the president has wide discretion when it comes to operational matters on the battlefield as well as establishing systems of intelligence-gathering. Despite the extraordinary imprudence and sustained incompetence of the Bush administration, presidents need leeway to act swiftly to meet often clandestine and changing threats. Congress cannot micro-manage actual military and intelligence operations.

But Congress can establish the overall legal framework within which military and intelligence operations occur, especially when they involve Americans living in America. In short, constitutional authority is concurrent in this area. When Congress has not acted, the president may step in. However, Congress may legislate, and expect the president to "take care that the laws be faithfully executed."

After all, contrary to the claims of those who imagine executive supremacy, the Constitution divides the government’s war-making powers, giving Congress authority for almost everything except operations. Article I, Section 8 authorizes Congress "To define and punish piracies and felonies committed on the high seas, and offenses against the law of nations; to declare war, grant Letters of Marque and Reprisal, and make rules concerning captures on land and water; to raise and support armies ; to provide and maintain a navy; to make rules for the government and regulation of the land and naval forces; to provide for calling forth the militia ; to provide for organizing, arming, and disciplining the militia ;" and "to make all laws which shall be necessary and proper for carrying into execution the foregoing powers."

Under these circumstances Congress may require warrants before the government may spy on American citizens in America, irrespective of the president’s wishes. (A recent opinion by the U.S. Foreign Intelligence Surveillance Court of Review defended FISA from constitutional challenge, not the Bush administration’s warrantless surveillance from congressional challenge.)

If the Bush administration believed that it needed more power, it had an obligation to go to Congress and propose changes, not to secretly violate the law. If there were truly exigent circumstances, the executive could have simultaneously initiated a surveillance program and requested additional legal authority. Congress almost certainly would have complied, since it  unwisely, in fact  rubber-stamped virtually every other administration request for power or money advanced in the name of national security. Indeed, the fact that the Democratic Congress later amended FISA in response to administration pressure demonstrates that, in former U.S. Attorney and congresswoman Elizabeth Holtzman’s words, "the president could have asked Congress to change the law from the outset."

Having chosen to violate the law, administration officials should be held accountable. At the very least that requires investigating and reporting on their actions. More likely that includes legal action against at least some of the actors.

The other obvious violation of the law is the use of torture. The argument against torture is powerful: claims that "enhanced interrogation" methods, as the administration preferred to call its practices, remain unproven assertions. In fact, counter-terrorism officials familiar with the most noted cases discount the information acquired as a result of torture. In general, they dismiss the value of intelligence procured under duress and emphasize alternative strategies for getting information. Even FBI Director Robert Mueller admitted that he didn’t "believe it to be the case" that the Bush administration’s tough interrogation practices prevented any terrorist attacks in the U.S.

Moreover, torture tarnishes America’s global reputation, threatening Washington’s ability to win the cooperation of friendly states in fighting terrorism. The practice also puts American forces at risk. A former special intelligence operations officer writing in the Washington Post under the pseudonym Matthew Alexander argued after his experience in Iraq: "It’s no exaggeration to say that at least half of our losses and casualties in [Iraq] have come at the hands of foreigners who joined the fray because of our program of detainee abuse."

Finally, torture erodes America’s moral core, so critical to what makes America worth defending. Notes Charles Fried of Harvard Law School, who also served as Solicitor General under President Ronald Reagan: "we cannot authorize indecency without jeopardizing our survival as a decent society."

Here, too, if President Bush believed that he lacked sufficient authority under the law to protect America, he should have proposed that Congress amend or repeal the law. He did not have the option to ignore it.

Of course, the Bush administration repeatedly said that it did not torture  less than a week before leaving office, White House Press Secretary Dana Perino emphasized: "Let me just make sure it’s clear  and I’ll say it on the record one more time  that it has never been the policy of this president or this administration to torture." But the contrary evidence is overwhelming. The fact that congressional Democrats were regularly briefed on the administration’s tactics spreads the blame rather than legitimizes the tactic.

Did the administration utilize torture? Don’t ask liberal critics of the Bush regime. Ask Jack Goldsmith, who headed the Office of Legal Counsel and revoked two earlier legal opinions authorizing coercive interrogation. Ask retired Lt. Gen. Antonio M. Taguba, tasked by the Pentagon with investigating the Abu Ghraib scandal: "There is no longer any doubt as to whether the current administration has committed war crimes. The only question that remains to be answered is whether those who ordered the use of torture will be held to account." Ask Robert Turner, a Reagan White House attorney who said that war crimes "may well have been committed." Ask Susan Crawford, a retired judge (and Republican) appointed by the Defense Department to decide whether to charge Guantanamo Bay inmates. She called the treatment of one Saudi inmate torture, contending: "The buck stops in the Oval Office."

In short, detainees were tortured. The only questions are how many people were tortured and who were responsible for the decision to use torture. To prosecute would not be to criminalize policy differences, but to punish a criminal policy.

The issue appears to have been debated at high highest levels of the White House if not in the Oval Office itself, and that’s where responsibility should be lodged. A bipartisan Senate Armed Services Committee report concluded that "senior officials in the United States government solicited information on how to use aggressive techniques, redefined the law to create the appearance of their legality, and authorized their use against detainees."

Of course, any investigation must be impartial and nonpartisan. Moreover, assessing blame becomes tougher as one moves down the chain of command. While no one wants to accept an "I was only following orders" defense, the cases become harder where intelligence or military personnel are relying on the Justice Department, which officially baptized improper conduct. Nor should a bad legal opinion result in criminal penalties, though bad lawyering should be exposed, and anyone who knowingly relied on a bad legal opinion acted unreasonably and thus should be held accountable. An investigation first should report what happened. Then prosecution decisions should be made, taking into account the full circumstances.

On the torture issue, at least, the administration may find it difficult not to prosecute. When Eric Holder told the Senate Judiciary Committee that waterboarding was torture, he was telling the nation that the Bush administration had violated the law. Noted Jennifer Daskal of Human Rights Watch: "It would be contrary to the principles of the criminal justice system for the attorney general to say he believes a very serious crime has been committed and then to do nothing about it."

The 1949 Geneva Convention and United Nations Convention Against Torture (both ratified by the U.S.) make it even harder to avoid the case. Indeed, the latter mandates that states prosecute potential offenders or extradite them to another country for prosecution. Law professors Anthony D’Amato and Jordan J. Paust, the latter a former faculty member at the Judge Advocate General’s School, argue that for this reason the president has "the duty to prosecute or extradite persons who are reasonably accused of having committed and abetted war crimes or crimes against humanity."

The Bush administration mercifully has concluded, but its malign impact lingers. President Obama must confront the Bush legacy. He has started the process by ordering the closure of Guantanamo Bay and end of torture, but he then must turn a spotlight on his predecessor’s policies, which were certainly abusive and likely illegal. And he must call to account those who implemented such policies.

Yes, the process may be divisive. Yes, assessing conduct and culpability won’t be easy. Yes, interrogators are likely to grow more cautious in the future. But we claim to be defending America’s constitutional order of limited government and individual liberty. The Bush administration committed serious crimes. The U.S. punished its own soldiers who used such tactics against Filipino guerrillas following the Spanish-American War, as well as Japanese officers who employed the practice in World War II. Salon columnist Glenn Greenwald points to the Bush Justice Department’s recent prosecution of the son of former Liberian President Charles Taylor for torture: "The gravity of the offense of torture is beyond dispute," opined the outgoing administration. If we merely wave good-by to those who have ostentatiously violated the law, what is to stop future law-breaking by future government officials, including against precisely these liberties?

Michael Ratner of Columbia Law School makes the obvious point that "The only way to prevent this from happening again is to make sure that those who were responsible for the torture program pay the price for it." The need for deterrence should be obvious from the fact that, notes Greenwald, "The same controversies over government lawbreaking arise over and over. And why is that? Because our political leaders keep breaking the law." Deterrence is important. Greenwald, who has written extensively on this topic, points to FBI officials, among others, who refused to cooperate in the use of torture out of apparent fear of criminal sanctions. But at some point the guilty must be punished else deterrence disappears.

Nevertheless, Washington’s usual suspects have ordained that the past should be forgotten, a bit of unpleasantness to be swept under the proverbial political rug as the bright future dawns with Barack Obama’s ascension to the presidency. For instance, David Ignatius of the Washington Post dismissed "liberal score-settlers" at a time when we should appreciate "the dangers America still faces from al-Qaeda and its allies." But no president should be immune from prosecution for breaking the law, irrespective of the challenges facing America. Dawn Johnson, the Indiana University law professor tapped to head the Office of Legal Counsel, which blessed torture early in the Bush administration, observed: "We must avoid any temptation simply to move on. We must instead be honest with ourselves and the world as we condemn our nation’s past transgressions and reject Bush’s corruption of our American ideals."

Put simply, moving on requires settling up. Is there a criminal defendant alive who wouldn’t like to see the government drop its prosecution in the name of "moving forward"? As Robert Jackson explained in his opening address to the Nuremberg Tribunal: the law must "not stop with the punishment of petty crimes by little people. It must also reach men who possess themselves of great power."

The process of settling up should be about law rather than politics. It should be conducted in sorrow rather than rancor. And it may mean far more investigation than prosecution. But the Constitution must be defended and the law enforced. By both the president and Congress. The people of America deserve no less.