The November terrorist attacks in Paris display clearly President Obama’s imperviousness to reality and his commitment to ideology. A small group of eight ISIS operatives used small arms and suicide vests to kill about 130 people, wound another 370, and shut down one of Europe’s great capitals for days. Obama’s response included not just a limp increase in ineffectual airstrikes and aid to Syrian rebels but a renewed focus on closing the terrorist detention facility at Guantanamo Bay, Cuba. While terrorists seek to launch more attacks on the West, the administration’s solution includes releasing more of their most dangerous leaders or bringing them into the United States.

Even before the start of his presidency, Barack Obama wanted to shut down Gitmo, as it is known. A strong bipartisan coalition has used Congress’s power of the purse to block his plans. Now, as his time in office draws to a close,

Obama and his advisers are suggesting that as commander-in-chief he has the constitutional authority to close the facility in defiance of federal statutory law.

Obama’s argument is not merely mistaken. It is irresponsible. In his seven years in office, Obama has already inflicted severe and perhaps irreversible damage on the separation of powers. Executive overreach has already become a staple of the administration’s policies on health care, immigration, education, and welfare. But to

close down Gitmo, in defiance of Congress’s clear, explicit, and repeated ban on the use of Defense Department funds to transfer prisoners to the United States, would cross into a frontier of lawlessness never before reached by any president.

In the words of Joseph Story, the great 19th-century scholar and Supreme Court justice, it would mean that henceforward “the executive would possess an unbounded power over the public purse of the nation; and might apply all its monied resources at his pleasure.”

If Obama’s legal apologists were right, then Presidents Nixon and Ford could have continued to fight the war in Vietnam even after Congress had cut off funds. Presidents could run domestic industries to keep arms flowing, choose the weapon systems that they like, and, ultimately, build an army and navy as large as they wanted.

Congress would be utterly without power to end a war that the president was determined to prolong.

These consequences are both dangerous and absurd. If Obama ignores Congress’s power of the purse, he will cross a red line and shatter the system hardwired into the Framers’ Constitution.

GUANTANAMO AND THE SEPARATION OF POWERS

The US Naval Station at Guantanamo Bay operates the only facility for the detention of enemy combatants captured in the war on terrorism. Contrary to popular perceptions, Gitmo does not run a prison like a federal supermax or state facility for the housing of criminals.

In war, nations can capture and hold prisoners, without criminal trial, until the end of the conflict.

The taking of prisoners has been a basic feature of war throughout human history, and the United States has detained prisoners in every war it has fought. “Lawful combatants are subject to capture and detention as prisoners of war by opposing military forces” owing to “universal agreement and practice,” the Supreme Court observed during World War II.

Nations hold enemy fighters to prevent them from returning to the fight. Over the past 15 years, the United States has held about 780 alleged terrorists at Gitmo. It has released or transferred most of them. Only 107 of the most dangerous, as even the Obama administration found them to be, remain. But the government has obviously been too hasty in its catch-and-release policies. US intelligence officials have confirmed that 17 percent of those who have left Gitmo have directly “re-engaged” in terrorist activities, while it suspects another 12 percent of the same.

Clearly worried about this 30 percent recidivism rate, Congress passed legislation to bar the transfer of detainees to the United States, thereby effectively keeping the prison open. Political opposition first arose in response to Obama’s abortive plan to transfer 9/11 mastermind Khalid Sheikh Mohammed and several other al-Qaeda leaders to New York City to stand trial. Obama only lived up to congressional suspicions last year by failing to give prior notice of an exchange of five Taliban detainees from Guantanamo for Army Sergeant Bowe Bergdahl, who is suspected of desertion in Afghanistan.

Despite threats of a presidential veto, the Obama administration has broadly acquiesced in Congress’s decisions. This year, however, Obama vetoed the legislative package in which the relevant restrictions were contained — the National Defense Authorization Act for Fiscal Year 2016. The NDAA/FY 2016 had easily passed both houses of Congress (with substantial support from Democrats). Given the crucial need for this major piece of annual legislation, it is possible that Congress will override the president’s veto by a two-thirds majority in each house.

The NDAA [National Defense Authorization Act] would prohibit Defense Department funds to be used to “transfer, release, or assist in the transfer or release,” into the United States or its territories, of (effectively) any non-US-citizen detainees held in Guantanamo, unless Congress approved a plan submitted by the Defense Department to dispose of all detainees. The NDAA also includes a similar funding bar with regard to the construction or modification of facilities in the United States to house detainees transferred from Guantanamo. Another funding prohibition bars the transfer of detainees to Libya, Somalia, Syria, or Yemen. A fourth provision restricts transfer to the detainee’s own country, except under limited conditions. Taken as a whole, the provisions foreclose the transfer of the detainees to the United States and severely limit their movement to other parts of the world.

Although the White House has claimed that it is seeking to work with Congress, it has failed for years to submit to Congress a plan for closing the facility. The Defense Department estimates that closing the facility would cost as much as $600 million, with $350 million up front in construction costs. When Defense Secretary Ash Carter provided the White House with that plan last month, Obama reportedly rejected it as too expensive and ordered the Pentagon to review the matter.

THE POWER OF THE PURSE: CONSTITUTIONAL TEXT AND HISTORY

The Constitution provides Congress with several powers that might regulate the disposition of captured enemy combatants. Congress’s power of the purse is codified in Article I, section, 9, clause 7 of the Constitution: “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law.” There has never been any doubt as to either the meaning or the purpose of this clause. In Federalist 52, James Madison explained:

The House of Representatives cannot only refuse, but they alone can propose the supplies requisite for the support of the government. They, in a word, hold the purse — that powerful instrument by which we behold, in the history of the British Constitution, an infant and humble representation of the people gradually enlarging the sphere of its activity and importance, and finally reducing, as far as it seems to have wished, all the overgrown prerogatives of the other branches of government. This power over the purse may, in fact, be regarded as the most complete and effectual weapon with which any constitution can arm the immediate representatives of the people, for obtaining a redress of every grievance, and for carrying into effect every just and salutary measure.

Likewise, Justice Joseph Story, an early and authoritative expositor of the Constitution, wrote that Congress has “a controlling influence over the executive power, since it holds at its own command all the resources by which a chief magistrate could make himself formidable. It possesses the power over the purse of the nation and the property of the people. It can grant or withhold supplies; it can levy or withdraw taxes; it can unnerve the power of the sword by striking down the arm that wields it.”

Congress’s power is further illustrated by its power to “raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years.” This clause shows that Congress can defund the Army every two years, or each time a new House of Representatives is elected. But if Congress can simply refuse to pay for an army, the commander-in-chief clause cannot enable the executive to maintain one if it so chooses. The scale and indeed the very existence of the nation’s military forces is entirely subject to congressional funding decisions.

Some Obama critics point to Congress’s authority, set out in Article I, Section 8 of the Constitution, to “make Rules concerning Captures on Land and Water” as the more central limit on the president’s Gitmo plans. These authors, including the Wall Street Journal editorial page, interpret the clause to include setting out the rules on prisoners of war. While we sympathize, we think the captures clause applies only to property, which once constituted a much more important element of the laws of war. The history of the clause shows that captures referred not to the taking of prisoners but to the seizure of enemy property. In previous American wars, Congress almost always deferred to the president on policy for the treatment of enemy prisoners and instead used its power to regulate the rules of prize, as they were once known.

The Supreme Court has consistently recognized the breadth and finality of Congress’s power of the purse. In Cincinnati Soap Co. v. United States (1937), it explained that the appropriations clause “was intended as a restriction upon the disbursing authority of the Executive department.” It meant that “no money can be paid out of the Treasury unless it has been appropriated by an act of Congress.” In United States v. MacCollom (1976), the Court affirmed that “the expenditure of public funds is proper only when authorized by Congress, not that public funds may be expended unless prohibited by Congress.” In Office of Personnel Management v. Richmond (1990), the Court stated that the appropriations clause is “a most complete and effectual weapon” of Congress because “any exercise of the power granted by the Constitution to one of the other Branches of Government is limited by a valid reservation of congressional control over funds in the Treasury.”

We are aware of only one president who arguably has gone in the direction in which Obama seems to be heading, and the contrast reveals the hollowness of the administration’s Gitmo claims. After the firing on Fort Sumter on April 12, 1861, President Abraham Lincoln called for volunteers, raised an army, sent troops into operations against the Confederacy, and ordered a naval blockade. To pay for the mobilization of federal power, Lincoln withdrew money from the Treasury without a prior appropriation. Congress would not meet until July 4, 1861, when called into special session by the president. In his special message at that session, Lincoln asked for and received the necessary authority and appropriations for the actions that he had taken during the emergency conditions of the first months of the war.

The contrast with Obama’s claims could not be sharper. Unlike today, Congress in 1861 had not passed any laws barring the use of funds to respond to secession. President Lincoln had to take immediate steps under the press of circumstances to prevent the dissolution of the nation — the very constitutional purpose of vesting the executive power in a single president — when no other branch of government could act. When it came into session, Congress promptly approved Lincoln’s decisions, and the Supreme Court, in the Prize Cases, subsequently upheld the legality of the president’s response to Fort Sumter.

Today, Congress has not merely failed to make appropriations for the purpose of closing Gtmo; it has deliberately, and for years, forbidden the use of appropriations for that purpose. And while Obama can claim that the commander-in-chief has a constitutional right generally to manage the detention of enemy prisoners, there are no emergency conditions here, nor any sudden threat as great as the outbreak of the Civil War, to justify overriding an outright ban on funding. Congress remains in session and could vote funds regarding Gitmo quickly, if it so chose. Lincoln acted during the greatest crisis ever to threaten our nation; Obama invokes the same power, in an even greater degree, to manage a policy dispute with Congress. Lincoln did not defy Congress, and could reasonably expect it to ratify his emergency decisions once it reassembled;

Obama would be defying Congress, and could hardly expect it to approve what he had done.

Obama’s claims also provide a pointed contrast to the counterterrorism policies of the Bush administration, in which we both worked. Much to the consternation of journalists and many professors (who have been strangely silent today), President Bush argued that Congress could not pass laws that interfered with his constitutional powers as commander-in-chief to wage war in response to the 9/11 attacks. Strategy and tactics, involving not just the use of force and management of the battlefield but the detention and trial of enemy prisoners, have traditionally fallen within the president’s executive powers. Congress can no more order the president how to use drones than it could have directed FDR to attack Japan first and Germany second. But President Bush never claimed the right to ignore funding prohibitions in the war on terrorism or in the conflicts in Afghanistan and Iraq. That constitutional red line has been respected by every president from George Washington on — except, perhaps, today.

CONCLUSION

Obama’s legal defenders have asserted that Congress’s spending bans are “irrational.” Even if that were so, however (and it is not), it would not relieve a willful president of his constitutional duty to comply with them. As the Supreme Court ruled in the 1978 “snail darter” case, TVA v. Hill, the executive has the constitutional obligation to enforce even an irrational policy (such as protecting an endangered species at the cost of wasting money already spent on constructing a dam) once Congress has decided on it. By vetoing the NDAA/FY 2016, Obama has reached the limit of his policymaking powers. If Congress overrides his veto, as seems likely, he has no alternative but to comply.

Liberals, if anyone, should be vigilant in upholding Congress’s power of the purse. That was their chosen vehicle for ending the Vietnam War. It was the centerpiece of their charges against the Reagan administration in the Iran-Contra affair. Do they really want to sabotage this basic constitutional authority for the sake of Barack Obama’s quest for a “legacy”? Are they willing to extend the commander-in-chief power to a truly grotesque extreme? Perhaps they do: We do not have high confidence in the fidelity of the American Left to constitutional principle.

But the American people know better. Obama’s utter and cavalier disregard for law while in office has already begun to trigger a reaction. Let his party and its candidates become the standard-bearers for lawlessness. They will eventually pay the price.

Robert Delahunty is Lejeune professor of law at St. Thomas School of Law. John Yoo is Heller Professor of Law at the University of California, Berkeley, and a visiting scholar at the American Enterprise Institute. They both served in the Justice Department during the George W. Bush administration.