“If the United States and its allies do not take military action against Syria in retaliation for the Assad regime’s use of chemical weapons against its own citizens, what will be the precedent set for the future, both in terms of deterring the use of such weapons and upholding international laws prohibiting them?”

Robert Wright, Future Tense Fellow, New America Foundation: This question evinces a concern with “upholding international laws.” Here’s another question that evinces such concern: What is the effect of the United States flagrantly violating international law by attacking a country without U.N. Security Council approval and without a self-defense justification?

And let’s be clear: It would be very dubious to cast a military action as an enforcement of international law on chemical weapons. Syria didn’t sign the Chemical Weapons Convention. And the Geneva Convention, which it did sign, doesn’t contemplate military punishment for the use of chemical weapons—and arguably doesn’t apply to a civil war anyway. So a US military strike against Syria would be about upholding the norm against chemical weapons use—a very important norm, to be sure—but not about enforcing international law in any clear-cut way.

Was there a way Obama could have stood up for that norm while showing proper respect for international law? I think so. Here’s what he could have done:

(1) Seek U.N. Security Council authorization of a punitive strike; (2) Fail to get such authorization, as Syria’s ally Russia exercises its veto; (3) Deliver a speech declaring that if there is another big chemical attack in Syria, then blood will be on the hands of nations that used their veto power to impede punishment of Syria. He could also say that if there’s another attack, he’ll again take the matter to the Security Council and challenge those who thwarted action this time to change course.

This would put Vladimir Putin in an uncomfortable position. Contrary to stereotype, creepy authoritarians do care what the world thinks of them. And since Putin, as a key weapons supplier to Syria, has leverage in Damascus, his discomfort would have impact. It would pretty much ensure that there were no more big chemical weapons attacks by the Syrian military.

This would be an imperfect solution. Ideally, anyone who uses chemical weapons would be punished. But this would have addressed the most urgent humanitarian objective—pre-empting the nightmare scenario of repeated and even escalating chemical attacks. And, unlike the solution Obama proposed, it would tell the world that, yes, the US will work to uphold important humanitarian norms, but it is committed to upholding international law as well.

Gabrielle Blum Rita E. Hauser Professor of Human Rights and Humanitarian Law, Harvard University: Using unilateral force to uphold the international legal prohibition on chemical weapons is itself a violation of an international legal prohibition. It means breaking the law to uphold the law. The question then is whether a certain degree of vigilantism is warranted in an international system whose law and order institutions – i.e., the Security Council – are deficient.

The chemical weapons attack of August 21 is not the first time such weapons have been employed in warfare. President Obama mentioned World War I in his speech; but of course, Saddam Hussein used chemical weapons to massacre thousands of Kurds in Halabja in 1988, and even more widely against Iranian forces during the Iran-Iraq war. In neither case did the international community intervene militarily. In fact, according to Shane Harris and Matthew Aid over at Foreign Policy, at the time, the United States provided Iraq with crucial satellite imagery of Iranian troop deployment, well aware that Iraqi forces would use chemical agents against them.

So what is different now? The United States is now the world’s leading superpower. And its interests are implicated in almost any conflict anywhere around the globe. And while Americans may resist the role of the “world’s police officer,” they are uniquely positioned to act in lieu of the designated but derelict world’s police officer – the Security Council.

This does not mean that the United States can or should jump into action whenever anyone breaks the law or disrupts the order. And upholding the U.N. system is itself an American interest. But when it comes to a vital interest such as upholding the ban on any and all use of weapons of mass destruction, and where the need for moral condemnation is so great that no rhetorical gesture could suffice to meet it, the United States might just have to be the world’s vigilante. That’s an unsatisfying, perhaps dangerous, reality, but the alternative – a world in which rogue powers are in the clear when using WMDs – is a far nastier one.

Barak Barfi, National Security Program Research Fellow, New America Foundation: As the possibility that the international community will punish Syria for its use of chemical weapons fades with each passing day, it is necessary to step back and examine how this episode will affect the proliferation and future use of weapons of mass destruction (WMD).

When the United States invaded Iraq in 2003, it declared that Baghdad’s possession of WMD was a casus belli. It has hinted that Iran’s efforts to acquire nuclear weapons would trigger the same. So when President Barack Obama proclaimed in August 2012 that ‘a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized,’ it was natural to view his comments as a continuation of America’s post-Cold War policy on WMDs.

The administration’s dithering on Syria has muddied these clear waters. It is too facile to view the Syrian example as ushering in a new policy of ‘use them if you can get away with it.’ Because whether inaction today will embolden future rogue actors to employ WMD will largely depend on the mitigating circumstances of their conflict.

If a terrorist group such as Hizballah were to obtain Syria’s chemical weapons arsenal, it would be conflicted about employing them. Launching sarin tipped missiles into Israeli population areas would certainly serve Hizballah’s goals of exposing Israel’s military vulnerabilities. But a disproportionate Israeli response would decimate the organization, leaving it no more than a group of isolated cells scattered throughout Lebanon. Such considerations would be given much more weight in the group’s deliberations than fear of an international strike.

Realists believe interests rather than international law drives foreign policy. The United States has few interests in Syria and even if it tried to secure them, it is doubtful it could do so militarily. Future conflicts may be of greater importance to Washington, thus compelling it to intervene. As a result, looking to the Syrian conflict as a precedent for the interdiction of WMD use is as futile as believing that an American military strike will persuade the regime not to employ them again.

Danielle Pletka, Vice President of Foreign and Defense Policy Studies, American Enterprise Institute: It’s important to start with the understanding that there are no provisions in the Chemical Weapons Convention that require anyone, least of all the United States, to “retaliate” against those who violate its terms. And as Syria isn’t a signatory to the convention, the notion of an international obligation is irrelevant. The more important question is whether the President of the United States, particularly one who demanded Assad step aside and laid down a “red line” on the use of chemical weapons, can simply punt rather than strike at the heart of Assad’s ability to deliver CW. As a matter of precedent, there is ample precedent for doing nothing; the Anfal campaign against Iraq’s Kurds saw chemical weapons used against innocent civilians without international reprisal.

Assad himself has used these weapons 14 times according to reports. Obama administration officials tell us this time is different, that weapons of mass destruction could fall into terrorist hands; that Assad could use them again, as could others. All the more odd, therefore, that the President now seems loath to prosecute a Syrian strike. The real message that Obama’s inaction will send is that the United States is no longer a player on the global stage, no longer an enforcer of international norms; no longer a power to be reckoned with. Forget Assad for a moment. How will the Islamic Republic of Iran read Obama’s decision?