The United States and Russia have now averted U.S. military action against the Syrian regime for Bashar al-Assad’s use of chemical weapons against civilians. Is the agreement reached by Secretary Kerry and Foreign Minister Lavrov on September 9 a diplomatic triumph for the Obama administration, or was it, as retired British ambassador Charles Crawford called it, “the worst day for U.S. and wider Western diplomacy since records began?”

While perhaps not as bad as Ambassador Crawford suggests, we agree that the outcome is one of the worst defeats for U.S. foreign policy in decades. We write as two scholars and former national-security practitioners who agree on almost nothing else regarding Syria: one is a traditional realist who opposed military action against Assad, and the other is a recent arrival in the camp of the post-Cold War liberal internationalists who supported striking the Syrian regime. We come not only from diverging views but also from different academic disciplines (history and political science), and while both of us have served in positions relevant to American foreign and security policy, we speak on our own behalf, especially since we ourselves are otherwise so deeply divided about U.S. intervention overseas.

We share, however, a background in the study of Russia, and it is here that we find the outcome of the Syrian crisis to be so disastrous. For nearly seven decades, American efforts in the Middle East have been based on a bipartisan consensus—one of the few to be found in U.S. foreign policy—aimed at limiting Moscow’s influence in that region. This is a core interest of American foreign policy: it reflects the strategic importance of the region to us and to our allies, as well as the historical reality Russia has continually sought clients there who would oppose both Western interests and ideals. In less than a week, an unguarded utterance by a U.S. Secretary of State has undone those efforts. Not only is Moscow now Washington’s peer in the Middle East, but the United States has effectively outsourced any further management of security problems in the region to Russian president Vladimir Putin.

We both deplore the hyperpartisanship that has required too many Republicans and Democrats to support or oppose this new agreement based on domestic political calculations. We recognize, however, that more sincere defenders of the September 9 deal see great virtue in it. They argue, for example, that it will avert the need for military force (a threat most Americans did not want carried out anyway), that it will strip Assad of his chemical arms without fighting, and that it will force Putin to take ownership of the WMD question in Syria and thus obligate Russia to live up to better standards of global citizenship.

We find these to be optimistic and hopelessly naïve interpretations. It will be nearly impossible to move chemical weapons anywhere in the midst of a pitched civil war; moreover, the idea that the Putin regime cares anything for international norms or global citizenship beyond its own crudely defined interests is laughable on its face. By gaining American certification of the most important role Moscow has ever played in the Middle East, Putin has achieved in a week what no Soviet or Russian leader managed to do in a century. There should be little wonder that Putin pressed his advantage with a shameless lecture to America in the pages of The New York Times in one of the most appalling and hypocritical public relations stunts by a Kremlin boss since the Soviet era.

Of course, we do not blame President Putin for seizing this opportunity. The Russians are behaving as we would expect them to. Rather, we are dismayed primarily because U.S. diplomacy seems to have forgotten the innate ruthlessness of Russian foreign policy. The President and his advisers may have earned their stripes in Chicago’s tough political hothouse, but the games of the Midwest do not compare to the hardball played in Moscow.

The repercussions of the Kerry-Lavrov deal will be with us for years to come, and so we had best recognize them realistically before we proceed another step.

First, the United States has now effectively abandoned its previous policy on Assad: recall that President Obama publicly called for regime change in Syria in August 2011, and the White House and Congress together later toughened sanctions designed to force Assad out. Supporters of the Kerry-Lavrov deal claim that regime change was never a part of the administration’s plans for striking Syria. Perhaps not, but U.S. policy has now been completely reversed, with a de facto acknowledgment of Assad as the leader of Syria and a pledge to leave him alone under his strengthened Russian protection. The opposite of “regime change” need not be “regime recognition,” but that is in effect the deal the Russians have wrested from us.

This is crucially important because we have risked sending a message to our allies from Seoul to Warsaw and beyond that our commitments are based on political expediency and short-term public opinion rather than principle. Who can blame uncertain governments around the world if they now conclude that Moscow, not Washington, is the reliable and trustworthy partner? Assad counted on the Russians and has survived to rule another day, which is more than our deposed Egyptian ally Hosni Mubarak can say. Franklin Roosevelt once famously said of a Central American dictator that he was a son of a bitch, but that he was our son of a bitch; Vladimir Putin has now made it clear that when Moscow says someone is their son of a bitch, they really mean it, in every way, and that the Kremlin will stand tough on his behalf. This is a message that will especially resonate in the Middle East, where perceptions of strength matter far more than the niceties of UN resolutions that will never be observed. Islamists who have argued all along that America is Osama bin Laden’s “weak horse” will not fail to note our retreat.

Finally, the U.S. has now been defeated in a major attempt to universalize even a barely minimal norm regarding the use of WMD. A rogue regime has gassed its own civilians, and will pay no price other than an insincere reprimand from its closest ally. While we disagree between ourselves about the wisdom of spreading such a norm—one favors it, the other sees it as a pointless effort—we agree that Syria was the worst possible place for such a campaign to collapse because of the obvious implications for any attempts to contain neighboring Iran. If we could not take a stand against Assad, why should the Iranian regime, or its armorers in Moscow, care about any further Western objections to Iran’s nuclear programs? And why shouldn’t the Israelis conclude not only that they are alone in the region, but also that their enemies can count on strong backing from Moscow?

The situation in Syria is probably, at this point, unrecoverable. Assad has used WMD, and will remain in power unless Moscow thinks he should not. The Syrian rebels will likely become more dominated by radical Islamists who will taunt their competitors about America’s abandonment. Moscow will arm its clients, including Iran, at will. And why not? After all, the Russians are now the officially sanctioned managers of WMD threats in the region.

If there is a policy solution, it begins in Washington. The President, his foreign-policy team, and Congress need to communicate with each other and present a more united face to the world. Nothing has provided more raw material for the Russians to work with than our own conflicting messages, contradictions, and internal squabbles. We can no longer press for Assad’s ouster, but we can make clear that one iota of noncompliance with this deal will result in a complete abandonment of the Kerry-Lavrov framework. (The President has tried to say this, but with so many qualifications the message was lost.) At that point, we may disagree about whether our next step should be to exact a short-term military price from Syria, to defang the Syrian military in a larger campaign, or to contemplate a new strategy for regime change in Syria. But the current situation, in which Moscow is now the arbiter of great power relations and the rules of war in the Middle East, is unsustainable. It is not only a defeat of the first order for the U.S. and the West in the region, but a danger to long-term peace and security around the world.

Tom Nichols and John Schindler are professors of national security at the Naval War College, and fellows of the International History Institute at Boston University. The views expressed are entirely their own.