Editors’ NoteThe following post is the fourth installment of a new feature, “Monday Reflections,” in which a different Just Security editor will take a longer view each Monday through a look back at the big stories from the previous week and/or a look ahead to key developments on the horizon.

One month ago, when the drums of war started beating, I suggested a legal strategy that the Obama administration might deploy to fight the Islamic State (ISIL or ISIS) in accordance with domestic and international law. In brief, I urged that: (1) under domestic law, the administration engage Congress proactively to secure a tailored ISIL-specific authorization to use military force (AUMF) to achieve those policy objectives that it shares with Congress and our allies, and (2) under international law, the administration ramp up diplomatic efforts to enlist support for military operations against ISIL by seeking a UN Security Council resolution defining the particular purposes for which multilateral action is authorized, including sanctions, humanitarian assistance, aid to responsible Syrian rebel groups who oppose both Assad and ISIL and the protection of civilians, refugees, NGO workers and journalists.

By now, everyone knows that the administration did not exactly follow that path. Instead, it proceeded with its ragged rollout of its legal grounds for fighting ISIL. With respect to the President’s position under domestic law, some hints leading up to the President’s ISIL speech on Sept. 10 were that the administration would rely on his Article II Commander-in-Chief powers, “welcoming,” but not specifically requesting, whatever congressional support might be forthcoming from a Congress eager to avoid voting on that issue just before the midterm elections.  The night the President spoke, unnamed administration sources told The New York Times that instead of relying on a pure Article II argument, the administration was resting its war against ISIL on an existing statute: the 2001 al-Qaeda AUMF—which the President had said in May 2013 he wanted to “refine and ultimately repeal.” Despite ISIL’s well-publicized rift with al-Qaeda, the administration’s one-paragraph legal justification claimed not that ISIL is a co-belligerent of al-Qaeda, but that it is effectively a “successor” to Osama bin Laden’s al-Qaeda. When this claim was derided by a range of commentators (e.g., Bruce Ackerman, Noah Feldman, Jack Goldsmith, Deborah Pearlstein, and Jonathan Turley), the administration confided to the Times that a different statute—the 2002 Iraq AUMF—also provided statutory authority for military action. Just a month earlier, White House National Security Adviser Susan Rice asked House Speaker Rep. John Boehner (R-Ohio) to repeal that law as well, saying that “the Iraq AUMF is no longer used for any US government activity.” All this reinforced the unfortunate impression that the government was making up its legal argument as it went along.  To make matters worse, the administration’s entire public legal analysis was an authorless “background statement from a senior administration official” emailed to the New York Times on Sept. 12. Meanwhile, as the controversy over the domestic legal case boiled, no one inside the United States government offered an international law basis for a conflict extending into Syria until the bombing was underway.

Thus, as of Sept. 23, when the administration notified Congress of significant strikes inside Syria against ISIL and the Khorasan Group under the War Powers Resolution, it had become conventional wisdom in some parts of the blogosphere that the conflict with ISIL is illegal. Despite their passion, remarkably few commentators and bloggers took the obvious next step: arguing, as John Hart Ely once did, that if Obama’s actions were so manifestly illegal, “[t]here is little legal doubt that such a serious and willful violation of the separation of powers should count as a ‘high crime and misdemeanor’ for purposes of the Constitution’s impeachment provision.” Yet even as the blogosphere churned, both the House and the Senate gave limited “buy-in” to the President by passing statutory provisions to fund training and equipping of moderate Syrian rebels before adjourning to campaign for re-election.

What should we make of where we are now? Did the Obama administration bungle its legal rollout? Clearly. But does that mean the President’s actions are clearly illegal? No. As I suggest below, both the domestic and international legal grounds for the ISIL conflict are defensible. At the same time, these grounds are shakier and less durable than they should be for a sustained conflict intended to degrade and ultimately destroy an evolving enemy. Four particular observations:

First, it’s déjà vu all over again. In retrospect, this sad saga is neither surprising nor new. Back in 1995, I listed some

basically pessimistic maxims that will likely govern the warmaking issue before the next presidential election. First, divided government invites executive unilateralism. Second, weak presidents are more dangerous than strong ones. Third …Congress will continue to try to avoid collective responsibility. … What history shows is that when government is divided, the political branches rarely reach a substantive consensus on war, much less any other kind of major policy decision. The prospect of deadlock makes it far more likely that the executive branch will resort to unilateralism in a crisis …. Yet this kind of executive unilateralism follows a reactive, not proactive pattern. The President perceives a threat, recognizes the need for American response, sincerely believes that he has a duty to act, but simultaneously realizes he can’t get Congress to support him. Rather than raising the issue openly and forcing Congress to vote on the question of approval, the President has powerful incentives to take another route. …. [T]he dominant game … will become what I call “Find the Statute,” or less colloquially, “The Hunt for Allegedly Delegated Prior Executive Authority.”… In the game, the President faces a foreign policy crisis, but does not ask the legislature for authority, fearing that it will be withheld. Instead, his lawyers search the US Code for preexisting statutes that they can claim already authorize the challenged activity. Congress will act affronted and might even hold hearings to complain, but deep down, the legislators are secretly relieved that the President, not they, will bear public responsibility for the policy, leaving them free to criticize and dissemble.

In the last few weeks, we have simply watched the same movie again. Whatever the President’s original intent with respect to seeking an ISIL-specific AUMF, the leaders of Congress disrupted it when they apparently asked him two nights before his speech not to seek a vote on a use of force bill before the midterm election. Finding no political support for his best option, the President faced two less palatable ones: (1) conduct a sustained war based on his Article II authority, notwithstanding his past criticism of his predecessor for abusing such authority, while arguing that the War Powers Resolution was unconstitutional (or otherwise did not apply) to avoid its impending 60-day clock; or (2) the “least worst” option, the one he ultimately chose: play “Find the Statute” and rely on both pre-existing AUMFs, even though he had previously—and I believe in good faith—indicated his desire to repeal them.

Second, despite the ragged rollout process, the administration has a defensible claim that its actions are lawful under domestic law. When all of his domestic authorities are laid out, the President can invoke four sources of legal support: (1) the 2001 al-Qaeda AUMF (2) with respect to actions in Iraq, the 2002 Iraq AUMF, (3) Congress’ train-and-equip legislation; and (4) whatever Article II authority he may be able to bring to bear to respond to those who would attack and kill US citizens.

As I understand it, the administration’s statutory theory is a fact-driven “splinter theory.” Under this theory, the 2001 al-Qaeda AUMF authorizes the fight against ISIL because the group began as al-Qaeda in Iraq (AQI), which the President considered part of bin Laden’s al-Qaeda (AQ Core), the organization that committed the Sept. 11, 2001, attack. After the US entered Iraq in 2003, AQ Core and AQI fought alongside one another—and eventually alongside al-Qaeda in the Arabian Peninsula (AQAP) and al-Qaeda in the Islamic Maghreb (AQIM) —against the United States from their respective geographic bases. These groups did not always share the same objectives, as evidenced by the fact that AQI eventually split from AQ Core, each group claiming to be the legitimate successor to bin Laden’s objectives. AQI renamed itself the Islamic State in the Levant (ISIL) to express its claim to be a caliphate. But even if ISIL and AQ Core do not share all objectives, they continue to share hostility toward the US and US interests, as shown by ISIL’s brutal beheading of American citizens it had captured, while taunting America’s President.

The 2001 al-Qaeda AUMF states that “the President is authorized to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001.” (Emphasis added.) As the statute permits, the President has apparently determined that AQI–and ISIL as its successor– was such an organization. The administration claims that when Congress adopted the 2001 AUMF, it did not intend to deny the President the authority to continue using force against an offshoot of AQ that later had a rift with AQ Core or changed its name, but not its anti-American objective. To do so would allow bona fide AQ splinters to publicly announce estrangements and thus avoid US force. The US was arguably empowered after it entered Iraq in 2003 to use the 2001 AUMF to fight AQI, but it did not need that authority as it had separate statutory authorization under the 2002 Iraq AUMF, which authorizes “The President … to use the Armed Forces of the United States as he determines to be necessary and appropriate in order to … defend the national security of the United States against the continuing threat posed by Iraq; and … enforce all relevant United Nations Security Council resolutions regarding Iraq.” Thus, as of today, under US law, the argument goes, both AUMFs may plausibly authorize the use of military force against ISIL inside Iraq, and the 2001 AUMF authorizes force against ISIL when it operates elsewhere, particularly in Syria.

The administration maintains that the limiting principle of this theory is factual: apart from ISIL, there are few, if any organizations that the President could plausibly determine satisfied this “AQ splinter” theory. That statute confers on him the power to make this determination, and he uniquely has the factual information before him to do so. While it is of course politically embarrassing that the administration had called for eventual repeal of both AUMFs, both nonetheless remain on the books as sources of legal authority. In another context, John Hart Ely famously criticized several administrations’ reliance on the infamous Gulf of Tonkin Resolution, but reluctantly concluded that until it was repealed, its literal terms nonetheless authorized the war in Vietnam.

There are undeniable problems with this theory. As I noted last month,

[t]he 2001 AUMF was enacted 13 years ago to prevent al-Qaeda and its co-belligerents from attacking the United States, not to fight a distant battle against a terrorist group that did not exist on Sept. 11, 2001, and has now clearly split from al-Qaeda. The 2002 AUMF for Iraq targeted the national security threat in Iraq, but was directed at Saddam Hussein, not ISIL, and at the unfounded fear that he possessed weapons of mass destruction.

The President has acknowledged that ISIL poses no immediate threat to the US homeland, the signature feature of bin Laden’s al-Qaeda. This limits his capacity to argue plausibly under either domestic or international law that he is acting in US national self-defense. More fundamentally, the “splinter theory” introduces a dangerous methodology whereby the current and future Presidents can cite “factual evidence of common AQ DNA” to declare war against a series of groups increasingly far removed from the al-Qaeda that Congress declared war against after Sept. 11, 2001. At a time when more than 60% of the American people believe the President should act militarily against ISIL, it should have been possible—and would have been far wiser—for Obama to secure an ISIL-specific AUMF, rather than proceed under his splinter theory. But he made a different choice. Politically, we may think it mistaken, even awful. But as lawyers, was it lawful?

My friend and colleague Bruce Ackerman recently argued that this is a matter for the courts to deal with and correct after the midterm election on November 6. But if the courts dealt with it and reached the merits—a most unlikely scenario—they would almost certainly uphold the President’s actions, accepting some version of the “splinter theory” articulated above. And what if they could not find express statutory authorization? Back in 1995, I suggested that if a private litigant could ever get such a case to a federal judge, “[t]he courts will invoke justiciability doctrines to try to avoid hearing private challenges to such cases, and if forced to decide on the merits, will defer to executive discretion, citing such cases as [the Supreme Court’s 1981 decision in] Dames & Moore v. Regan.…” If they did, they would probably quote from this language in the majority opinion, written by Justice Rehnquist during the term that his law clerk was a young lawyer named John Roberts:

Concluding that neither [statute] constitutes specific authorization of the President’s action …, however, is not to say that these statutory provisions are entirely irrelevant to the question of the validity of the President’s action. We think both statutes highly relevant in the looser sense of indicating congressional acceptance of a broad scope for executive action in circumstances such as those presented in this case…. Although we have declined to conclude that [either of these two statutes] directly authorizes the President’s [actions] for the reasons noted, we cannot ignore the general tenor of Congress’ legislation in this area in trying to determine whether the President is acting alone or at least with the acceptance of Congress. … Congress cannot anticipate and legislate with regard to every possible action the President may find it necessary to take or every possible situation in which he might act. Such failure of Congress specifically to delegate authority does not, “especially . . . in the areas of foreign policy and national security,” imply “congressional disapproval” of action taken by the Executive. On the contrary, the enactment of legislation closely related to the question of the President’s authority in a particular case which evinces legislative intent to accord the President broad discretion may be considered to “invite” “measures on independent presidential responsibility.” At least this is so where there is no contrary indication of legislative intent and when, as here, there is a history of congressional acquiescence in conduct of the sort engaged in by the President….

More than a quarter-of-a-century ago, I criticized this “implicit authorization” argument in Dames & Moore, but it and other overbroad Supreme Court opinions remain on the books. One could argue that this language should be limited to the specific issue in that case—settlement of international claims—and not extended to the warmaking arena, where Congress can cite to both the “Declare War” clause and the War Powers Resolution as requiring more explicit legislative approval.  But if the current warmaking situation ever got to court, there seems little doubt that the President’s actions would stand—whether on justiciability or on the merits—citing either the express or implicit authorization arguments outlined above.

Do I like this state of affairs? Hardly. As a constitutional matter, sustained wars require congressional approval, not just ambiguous “buy-in.” But this recurrent combination of executive initiative, congressional acquiescence and judicial tolerance is precisely why, as I wrote more than a quarter of a century ago, the President almost always wins in foreign affairs. This same historical pattern virtually ensures that, whatever the bloggers may say, what this President has done will never be found illegal, much less impeachable.

Third, despite the ragged rollout process, the administration currently has a reasonable claim that its actions are lawful under international law. My friends Jennifer Daskal, Ashley Deeks and Ryan Goodman recently made as strong a case as could be made that for now, the campaign in Syria against ISIL is not inconsistent with international law. Over the last few weeks, the President and the Secretary of State ramped up diplomatic efforts, and enlisted a growing coalition of allies, including five Arab countries—Australia, Bahrain, Belgium, Denmark, France, Jordan, UAE, Qatar, Netherlands, Saudi Arabia, and the United Kingdom—to lend military support in the fight against ISIL. Just this week, with President Obama in the chair, the UN Security Council unanimously adopted —without Russian objection—Resolution 2178, which obliged member nations to “prevent and suppress the [financing,] recruiting, organizing, transporting or equipping” of foreign terrorist fighters. And US Ambassador to the United Nations Samantha Power sent an “Article 51 letter” to Secretary-General Ban Ki Moon stating that “[s]tates [like the United States and Iraq] must be able to defend themselves, in accordance with the inherent right of individual and collective self-defense, as reflected in Article 51 of the UN Charter, when, as is the case here, the government of the State where the threat is located [Assad’s government in Syria] is unwilling or unable to prevent the use of its territory for such attacks.”

As Daskal, Deeks and Goodman note, this argument seems “sound, so long as the force used is necessary to protect against the direct threat that ISIS poses to Iraq, and that the amount and nature of force is proportionate to suppressing that threat.” Still, the international law argument remains too fragile to sustain an extended conflict that extends inside Syria. The Korean War, for example, began as US action in collective self-defense of South Korea, but the Truman administration persisted in securing a Security Council Resolution (in Russia’s absence), while calling it a “police action” to explain away the absence of a domestic declaration of war. Several coalition members—including Belgium, Denmark, and the United Kingdom—have now pointedly declined to support strikes in Syria, revealing that the coalition members are far more comfortable claiming that, for now, they are acting based on Iraqi consent, rather than claiming that they are engaged in self-defense of Iraq, their own homeland or immediate interests. An argument based on individual or collective self-defense argument is not robust or durable enough in the longer term to sustain the President’s ambitious stated goal of “destroying” ISIL, particularly in Syria.

Fourth, where do we go from here? While the administration has not acted illegally, the President needs to avoid four legal traps going forward: never justifying, never limiting, never expressly authorizing, and never repealing.

First, as a matter of domestic and international law, this issue is far too important to be justified publicly by terse anonymous emails to the New York Times. As Legal Adviser of the State Department, I argued that government lawyers have a “duty to explain” why they believe the President’s actions are lawful. The British Government submitted just such an explanation to the House of Commons to secure its vote supporting the US operation in Iraq. For that reason, the administration should lay out in greater detail its public legal justification for its actions under domestic and international law, including explaining with public facts why it believes that ISIL and the Khorasan Group are sui generis “splinter groups” of bin Laden’s al-Qaeda, and hence lawfully subject to 2001 AUMF authority.

Second, neither the President nor Congress wants to be drawn into using American ground troops in Iraq or Syria. Yet if they are relying on the 2001 and 2002 AUMFs, there is also apparently statutory authority to do whatever a future President might deem “necessary and appropriate” without further congressional input, including committing boots on the ground. It is worth rereading John Hart Ely’s War and Responsibility to remind oneself of how easy it is to slide down the slippery slope of mission creep, ground troops, and reluctant appropriations to “protect our soldiers in the field.” If Congress and the President genuinely agree that we need a statutory restriction on ground troops, then when Congress returns after the midterm elections, it should enact one, worded similarly to the House resolution that passed overwhelmingly in July.   This President should sign that restriction so he can tie himself—and more importantly, his successors—to that mast.

Third, saying that the President currently has the congressional authorization he needs does not give him tailored authorization to bring this conflict to its proper conclusion. If the lame-duck Congress has enough of a sense of responsibility—or at the least, reduced insecurity—it should work with the President, without the pressure of the election, to enact the ISIL-specific AUMF it should have enacted in the first place. Again, there is precedent for this: in 1983, Congress enacted the Multinational Force in Lebanon Resolution, which ratified the President’s unilateral use of force there, but placed important limitations on that statutory authority with respect to scope and duration. For the same reason, at the UN, the US should not rest on the Security Council Resolution passed this week, but should persist in seeking a resolution authorizing the use of force under Chapter VII of the UN Charter. Even if the Russians cast a veto, present and potential coalition members will be far more likely to support the US over the long term if they believe the US is making a good-faith effort to secure Chapter VII authorization to use force.

Fourth and finally, the President should stick to his wise goal of refining and eventually repealing both the 2001 and the 2002 AUMFs. In Senate testimony this past May, I suggested in some detail what a refined AUMF might look like, with a sunset clause, strengthened reporting requirements, limitations on substantive authority, and an ex post review mechanism. Such legislation would acknowledge that we have no national interest in using force in Iraq forever. Continued reliance on a “splinter theory” interpretation of the 2001 al-Qaeda AUMF threatens to undermine one of the President’s most important accomplishments: narrowing the 2001 AUMF to the achievable aim of dismantling particular terrorist networks that directly threaten us, as opposed to fighting an endless Global War on Terror against each new terrorist group that claims to be the successor to bin Laden’s mantle. If future presidents claim on weaker factual grounds that every terrorist organization that comes along—including groups that do not yet exist—are “AQ splinters” or successors, this moment will unintentionally become the turning point when President Obama stopped trying to end the “Forever War” and instead perpetuated the Global War on Terror.

Achieving a better outcome is not politically impossible. Representative Adam Schiff’s proposed AUMF, for example, would accomplish in one bill three of the four steps described above. It would (1) authorize “all necessary and appropriate force against ISIL” for eighteen months, limited geographically to Iraq and Syria and operationally to no US ground forces; (2) repeal the 2002 Iraq AUMF now and (3) repeal the 2001 al-Qaeda AUMF in eighteen months. If the President openly backed such legislation, it would place his war with ISIL on a much firmer legal ground, while advancing his longer-term objective—announced in 2013 at the National Defense University —of taking us off a permanent war footing.

This President came to office to end war. But he just declared a new one, sparing Congress of its constitutional responsibility to back him. Instead of breaking the vicious cycle, and asking Congress to live up to its constitutional duties to confront the Islamic State, the President prolonged a dysfunctional historical pattern that is inconsistent with the design of our National Security Constitution. As the conflict with ISIL stretches on, pressure will build to send advisers and other boots on the ground to further the goal of destroying ISIL. Americans and the world will grow weary and forget the exigencies that led this President to take this course.

There is still time to avoid this vicious cycle. When Congress returns, some will be lame ducks, and for all, the next election will be at least two years off. If members of Congress seriously care about their prerogatives, they will have no excuse for again ducking their constitutional responsibility. And this President will have those same years to consider what his constitutional legacy will be. History will treat this President far better if he leaves office not just having fought the Islamic State, but having lived up to his promise to put us on the path toward ending the Forever War.