We may be at a turning point in the Syrian agony, when diplomatic action combined with the threat of force moves the Syrian regime toward putting its chemical weapons under international control. If this happens it will be a victory for international law, for the authority of the UN Security Council, and for peace. But it is only too obvious that thus far the peoples of the democratic states have failed in our responsibility to protect the people of Syria.

This is hardly a failure to intervene: external intervention has been constant from the beginning. A ferocious, well-armed proxy war is devouring Syria, with weapons pouring in from all sides. Iran, Russia, Saudi Arabia, Turkey, the Gulf States, and Hezbollah have each tried to tip the military balance in favor of the regime or the rebels. Far from succeeding, they have aggravated the atrocities and exposed civilians on every side to repeated, deliberate, and murderous attack. The doctrine of Responsibility to Protect, or R2P, defines the protection of civilians as the sole legitimate reason for the use of force besides self-defense. Developed by an international commission of which I was a member, it has been endorsed over the past decade at least in principle by almost all UN member states. If our goal is to protect civilians in Syria, the R2P doctrine clearly suggests that further supplies of weapons to any side will only make matters worse.

The closest that the international community has come to applying this doctrine in Syria came when the Security Council dispatched Kofi Annan and then Lakhdar Brahimi to seek a cease-fire. Both attempts failed. Russia and China’s opposition has made it impossible to secure Security Council approval for no-fly zones, humanitarian corridors, or other measures that could have protected civilians from the brutality of the regime—and the reprisals of the rebels. Russia in particular has done its best to render the responsibility to protect inoperative, shipping weapons to a tyrant while lecturing the world on respect for international law.

In situations like Syria where the Security Council refuses to authorize force, the states that act alone or in concert with others will lack legal authority to do so. For Russia and China, and for many international lawyers, the matter ends there. If there is no legality, there cannot be legitimacy; and if there is no legality, any use of force in defiance of the Security Council weakens international law.

But the matter does not end there. When the Security Council blocks action and states get away with gassing their own people or killing them en masse, the rule of law suffers and the authority of the Security Council is diminished. It also suffers when rebel groups commit atrocities that go unpunished. States that act to defend civilians in the absence of Security Council approval have political, if not legal grounds to argue that they are, in fact, defending international law.

The fact is that what law forbids conscience may still command. What law forbids international peace and security might still require. What is legal is not always legitimate. Those who argue that international legality is the sine qua non for legitimate action in the international arena ignore the fact that there are situations of extreme necessity in both domestic and international law where obeying the strict letter of the law may allow a greater harm to occur.

When legality and legitimacy part company, as they have done in Syria, those who say strict legality must prevail have an obligation to explain how this squares with morality, just as those say that morality should prevail need to explain why they are justified in breaking the law.

A veto at the Security Council against protecting civilians in Syria has moral consequences. Such vetoes enable a ruler to continue butchering his own people and driving millions into exile. If a veto has these ghastly consequences, who would call it legitimate? Who would dare believe that such a veto strengthens the rule of law?

Equally, when legal authorization is not forthcoming, states contemplating military action had better find the grounds in moral necessity that they lack in law. Because they lack legality, they are under a special burden to demonstrate legitimacy. A state or international organization taking such action must show that peaceful means have been exhausted, that the force applied is strictly to protect human beings, that it will do more good than harm, and that it stands a reasonable chance of protecting civilians from further threats. Any external use of force in Syria or anywhere else has to meet such criteria.

If the proposed intervention does pass this threshold and the Security Council still refuses to act, where can the intervener turn to secure legitimacy? The issue that now confronts the international community is whether, in the absence of international legal authorization, the use of force can be legitimate if it secures democratic ratification.

The strong states, who do intervene in civilian protection cases, happen to be democracies. Their obligation to justify force and discipline its use derives from the governing constraints of democratic rule itself. The president’s recent decision to seek authorization from Congress in effect seeks to substitute democratic legitimacy for international legality. But there is a price that he has to pay. He has to prove to Congress that he won’t put Americans in harms way or ensnare them in Syria’s civil war. When democracy becomes the venue for testing the legitimacy of force, the bar of justification is set high, as both the President and the British Prime Minister have discovered.

Democratic people’s reluctance to use force is not a passing phenomenon, born of war weariness or disillusion with Iraq. It is an enduring feature of democratic politics itself. When the people themselves bear the cost of war, they have shown themselves reluctant to authorize it. It is hard to avoid the conclusion that once democratic consent becomes a condition for intervention, force will be rarely used indeed. This is as it should be.

But this means that even a justified intervention may founder with a reluctant public who fear that it commits democracies to over-extended, over-ambitious, and hubristic exercises in regime change. It is not enough to argue that an intervention to protect civilians seeks to strengthen rather than undermine sovereignty. True enough, but when preventive measures fail, when the immovable force of a regime fighting for its survival confronts the irresistible object of a civilian insurrection, the question for outsiders necessarily becomes whether to bring the regime down. Such was the case in Kosovo and Libya, and it is now the question in Syria.

In these conflicts, all parties involved attempt to play to the consciences of democratic peoples. The regime calibrates its repression to see what it can get away with. The rebel side seeks to trigger intervention with calculated provocations. We do the people we are trying to protect no moral favors if we insist that they only deserve rescue if they are helpless innocents. Intervention can only proceed once impartial observers—like the UN chemical weapons inspectors—have established who is actually responsible—regime or insurgents—for the crimes that trigger intervention.

But the deeper question remains whether you can protect civilians without overthrowing the regime that is oppressing them. This question haunts us as we try to figure out what to do in Syria. After more than two years of conflict, one that is increasingly shaped by proxies pouring in weapons, we may ask how any external intervener, including the United States, can hope to tilt the military balance decisively and force the regime to surrender. (If the US decided to send in ground forces and enforce a no-fly zone, it could eventually bring the regime down, but such an intervention lacks all political support either at home or abroad.) Unlike in Kosovo, there is no common political front and no common chain of command in the Syrian opposition, and hence no discernible possibility of aligning airpower with a cohesive unit that can be assisted to victory.

By the responsibility to protect standard, simply “punishing” a regime for using chemical weapons makes no sense. A more coherent strategy, if negotiations fail and conflict resumes, would be to degrade the regime’s capacity to harm civilians. Even if his capabilities are degraded, however, we can assume Assad will fight on unless the Russians and Iranians tell him the game is up.

In supporting an effort to bring Syria’s chemical weapons under international control, Russia now appears to have changed tack and we can only speculate why: Russia may fear that a US strike would weaken and topple its ally; or perhaps it no longer trusts Assad to control Syria’s chemical weapons and fears they may fall into the hands of the extremist networks that extend from Syria to the southern Russian frontier itself. Russia may be realizing that it too has strategic interests in enforcing the ban on the use of chemical weapons. If Russia can agree with other UN Security Council members to force Assad to abandon chemical weapons, the path to a cease-fire might lie open, for the first time.

A cease-fire, however, is impossible until all external interveners supporting the proxy war—including Saudi Arabia and Qatar as well as Iran and Russia—begin to understand that neither Assad nor the rebel side is going to emerge victorious and that the longer the conflict goes on the more harm it does to civilians and to peace and stability in the whole region.

From stalemate comes a ray of hope, the hope that all the external sponsors of the conflict will begin to reduce weapons supplies to all sides. A strategy of asphyxiation could be followed by concerted pressure at the UN for a negotiated cease-fire. If no side can win it all, it is just conceivable that each may settle for what it already has. The result would be a divided Syria, with Assad in sovereign control, but with effective authority in the north and east in rebel and Kurdish hands.

Leaving Assad in place, in other words, may be the only way we can protect civilians from carnage without end. An uglier trade-off between peace and justice is hard to imagine, but continuing to demand Assad’s departure, in the absence of any effective means to force him out, has become an empty threat and an even emptier strategy.

In other words, the protection of civilians in Syria depends on the resumption, at the earliest possible opportunity, of cease-fire negotiations in Geneva. Keeping open the threat of a limited, targeted strike on Assad, while negotiations over the chemical weapons program continue, is essential both for reaching a chemical weapons agreement and for sustaining the momentum necessary for an eventual cease-fire. This may be a faint hope, but it is the direction in which western policy should be headed. The alternative is years of civil war and further death and destruction.

The prize—successful control or confiscation of chemical weapons and an eventual cease-fire—is not merely an incalculable good for global security and for the lives of untold Syrians. It is the success we need in order to reinvigorate democratic faith in the capacity of the international community to protect civilians from tyrannical brutality.

Adapted from the Gareth Evans Lecture, Global R2P Center, New York City,

September 12, 2013