Imagine that U.S. agents nab a terrorist who knows the location of a ticking nuclear bomb and receive authorization from the president to torture him. Torture violates the law. So what happens next? Many people think the answer is straightforward. The agents and the president would face trial, conviction, jail time. The law is the law, and applies to everyone.

But there is a tradition of liberal political thought that suggests otherwise. Many of the American founders, influenced by Locke, believed in executive prerogative—the doctrine that the president enjoys the power to do what he believes is necessary to protect the country from threats to its security. The Constitution gives lawmaking authority to Congress, but general laws passed during times of peace cannot anticipate all the contingencies that arise in an emergency, and Congress is ill-equipped to pass new laws after the emergency has begun. If the president does not have discretion to take emergency actions that lack legal authorization or even violate existing laws, he will not be able to protect the nation. But if the president does have discretion to take actions he believes are necessary during an emergency, what prevents him from crowning himself dictator?

Benjamin Kleinerman offers a way out of this dilemma. He argues that the president needs the discretionary power to disregard the law during emergencies, but also that actions taken pursuant to this power should not be regarded as within his legal power. The president may use his “extra-constitutional” authority to take such actions if they are necessary to protect the nation; the actions must be taken during “extraordinary” rather than ordinary times, and they must not reflect the president’s personal views about what is morally important or politically expedient. If the president does not satisfy these conditions, the public must pressure Congress to impeach him. If he does satisfy them, his actions undergo a kind of constitutional baptism that washes away the taint of illegality.

Consider the example of Abraham Lincoln, who is Kleinerman’s hero. In the Emancipation Proclamation, Lincoln confiscated the property of slave owners without congressional authorization or legal process—a clear violation of the law at the time. But the Emancipation Proclamation was a military necessity in the war against the Confederacy. It was not motivated by a moral repugnance of slavery; that is why Lincoln did not emancipate all slaves, such as those in the friendly border states. And because this action took place during extraordinary times, it did not set a precedent that the executive can unilaterally confiscate property whenever it wants to do so. Lincoln acted outside of the Constitution, but because the people ultimately validated his actions, his actions became constitutional. (For unexplained reasons, it was sufficient that Northerners delivered this validation while Southerners remained mute.)

Kleinerman lambasts George W. Bush for not following this formula and instead claiming constitutional authority to protect the country using whatever means necessary. But Kleinerman cannot make up his mind about the ill consequences of Bush’s actions. He says that Bush has created dangerous precedents that will allow future executives to engage in abuse, but also that Bush might inspire a legalistic backlash that will prevent future executives from protecting the nation, and even that Bush will have created insufficient discretion for future executives because even Bush’s lawyers acknowledge that certain legal constraints remain. All three cannot be the case. Meanwhile, Lincoln, according to Kleinerman, avoided these bad consequences by acting extra-constitutionally. Lincoln established no legal precedents, while preserving maximal extra-constitutional discretion to address emergencies in the future. But why should it matter whether the precedent is legal or political?

To support this argument, Kleinerman makes some tricky assumptions about political psychology. He claims that the public is apathetic about government but fretful about security. If an emergency strikes, people eagerly put their faith in a president who takes a muscular response. If they believe that the president has the legal right to disregard statutes in emergencies, they are likely to acquiesce in an executive response that is unwise and even abusive. If they believe that the president has no such right, so that the president will have to claim extra-constitutional powers to break the law, they will be in a better position to judge the extent to which he upholds constitutional values, so that constitutional structures may be re-established when normal times return. Congress, in turn, can more easily impeach a president who abuses his discretionary power if emergency actions taken by the executive are regarded as extra-constitutional than if they are regarded as legal under the Constitution. 

This is pretty fancy footwork for the public, and even for its leaders in Congress—whom Kleinerman does not trust to act responsibly during a crisis, which is why he prefers discretionary powers for the executive to a role for Congress in emergencies. If the public forgives the president for violating the law during one emergency, that act establishes a precedent which a subsequent president will cite during the next emergency. This precedent is political, not legal; but the two types of precedent tend to merge in practice. Many of the legal powers enjoyed by the executive today evolved as a result of congressional, judicial, and public acquiescence in claims to authority by past presidents that were legally questionable but politically justified at the time.

The same is true for executive prerogative. Every president who has exercised emergency powers has claimed the legal authority to do so. Bush and Lincoln did not act as differently as Kleinerman says. The Emancipation Proclamation anticipated Bush’s executive orders by locating the president’s authority to free the slaves in his constitutional commander-in-chief power. Bush’s lawyers, like Lincoln, noted the extraordinary circumstances of the claim to power—it was wartime in both cases, and in both cases military necessity was thought to justify the actions. And although Lincoln acknowledged constitutional difficulties in a way that Bush did not, the presidency was a far weaker institution in 1861 than it is today. By neglecting the development of presidential power starting with the New Deal in 1933, which involved vast delegations of power from Congress to the executive to address emergencies, Kleinerman misses a big part of the story. Today, presidents can almost always find what authority they need in statutory law, judicial precedent, and the examples of their predecessors.

If Kleinerman’s argument is finally unconvincing, his book nonetheless offers many rewards. Hobbes, Locke, Hamilton, Madison, Jefferson, and Lincoln march splendidly across its pages, dispensing wisdom in extraordinary prose. The Americans in that group of authorities all agreed that the president of the United States must have the discretionary authority to disregard laws where necessary to address an emergency. They disagreed about whether the president enjoys implicit constitutional authority to take these actions or must act outside the Constitution. This distinction mattered to the founders and to Lincoln because they had to explain how their visions of limited government left the executive the discretionary powers it needs to protect the nation. But history settled the debate. Executive prerogative has been institutionalized. The only remedy for abusive behavior by presidents is political: in impeachment or at the polls.

Eric A. Posner is a professor at the University of Chicago Law School.