NEW YORK – The ongoing bloodletting in Syria is not only the world’s greatest humanitarian disaster by far, but also one of its gravest geopolitical risks. And the United States’ current approach – a two-front war against the Islamic State and President Bashar al-Assad’s regime – has failed miserably. The solution to the Syrian crisis, including the growing refugee crisis in Europe, must run through the United Nations Security Council.

The roots of US strategy in Syria lie in a strange– and unsuccessful – union of two sources of American foreign policy. One comprises the US security establishment, including the military, the intelligence agencies, and their staunch supporters in Congress. The other source emerges from the human-rights community. Their peculiar merger has been evident in many recent US wars in the Middle East and Africa. Unfortunately, the results have been consistently devastating.

The security establishment is driven by US policymakers’ long-standing reliance on military force and covert operations to topple regimes deemed to be harmful to American interests. From the 1953 toppling of Mohammad Mossadegh’s democratically elected government in Iran and the "other 9/11” (the US-backed military coup in 1973 against Chile’s democratically elected Salvador Allende) to Afghanistan, Iraq, Libya, and now Syria, regime change has long been the coin of the US security realm.

At the same time, parts of the human-rights community have backed recent US military interventions on the grounds of the "Responsibility to Protect,” or R2P. This doctrine, adopted unanimously by the UN General Assembly in 2005, holds that the international community is obliged to intervene to protect a civilian population under massive attack by its own government. In the face of the brutality of Saddam Hussein, Muammar el-Qaddafi, and Assad, some human-rights advocates made common cause with the US security establishment, while China, Russia, and others have argued that R2P has become a pretext for US-led regime change.

The problem, as human-rights advocates should have learned long ago, is that the US security establishment’s regime-change model does not work. What appears to be a "quick fix” to protect local populations and US interests often devolves into chaos, anarchy, civil war, and burgeoning humanitarian crises, as has happened in Afghanistan, Iraq, Libya, and now Syria. The risks of failure multiply whenever the UN Security Council as a whole does not back the military part of the intervention.

The US intervention in Syria can also be traced to decisions taken by the security establishment a quarter-century ago to overthrow Soviet-backed regimes in the Middle East. As then-Under Secretary of Defense Paul Wolfowitz explained to General Wesley Clark in 1991: "We learned that we can intervene militarily in the region with impunity, and the Soviets won’t do a thing to stop us… [We’ve] got about five to ten years to take out these old Soviet ‘surrogate’ regimes – Iraq, Syria, and the rest – before the next superpower [China] comes along to challenge us in the region.”

When al-Qaeda struck the US on September 11, 2001, the attack was used as a pretext by the security establishment to launch its long-desired war to topple Saddam. When the Arab Spring protests erupted a decade later, the US security establishment viewed the sudden vulnerability of the Qaddafi and Assad regimes as a similar opportunity to install new regimes in Libya and Syria. Such was the theory, at any rate.

In the case of Syria, America’s regional allies also told President Barack Obama’s administration to move on Assad. Saudi Arabia wanted Assad gone to weaken a client state of Iran, the kingdom’s main rival for regional primacy. Israel wanted Assad gone to weaken Iran’s supply lines to Hezbollah in southern Lebanon. And Turkey wanted Assad gone to extend its strategic reach and stabilize its southern border.

The humanitarian community joined the regime-change chorus when Assad responded to Arab Spring protesters’ demand for political liberalization by unleashing the army and paramilitaries. From March to August 2011, Assad’s forces killed around 2,000 people. At that point, Obama declared that Assad must "step aside.”

We don’t know the full extent of US actions in Syria after that. On the diplomatic level, the US organized the "Friends of Syria,” mainly Western countries and Middle East allies committed to Assad’s overthrow. The CIA began to work covertly with Turkey to channel arms, financing, and non-lethal support to the so-called "Free Syrian Army” and other insurgent groups operating to topple Assad.

The results have been an unmitigated disaster. While roughly 500 people per month were killed from March to August 2011, some 100,000 civilians – around 3,200 per month – died between September 2011 and April 2015, with the total number of dead, including combatants, reaching perhaps 310,000, or 10,000 per month. And, with the Islamic State and other brutal extremist groups capitalizing on the anarchy created by the civil war, the prospect of peace is more distant than ever.

Military intervention led or backed by the US in Afghanistan, Iraq, and Libya has produced similar debacles.

Toppling a regime is one thing; replacing it with a stable and legitimate government is quite another.

If the US wants better results, it should stop going it alone. The US cannot impose its will unilaterally, and trying to do so has merely arrayed other powerful countries, including China and Russia, against it. Like the US, Russia has a strong interest in stability in Syria and in defeating the Islamic State; but it has no interest in allowing the US to install its choice of regimes in Syria or elsewhere in the region. That is why all efforts by the UN Security Council to forge a common position on Syria have so far foundered.

But the UN route can and must be tried again. The nuclear pact between Iran and the Security Council’s five permanent members (the US, China, France, Russia, and the UK) plus Germany, has just provided a powerful demonstration of the Council’s capacity to lead. It can lead in Syria as well, if the US will set aside its unilateral demand for regime change and work with the rest of the Council, including China and Russia, on a common approach.

In Syria, only multilateralism can succeed. The UN remains the world’s best – indeed its only – hope to stop the Syrian bloodbath and halt the flood of refugees to Europe.

Jeffrey D. Sachs is a Professor of Sustainable Development

Copyright: Project-Syndicate.