Deploying air assets to Syria would certainly entail substantial risks to Western air forces and would require real intensity to tilt the balance toward the rebels. Syria in 2013 can field a far more sophisticated air-defense network and a larger air force than Libya could have in 2011. Syria appears to have about 450 Russian-made aircraft and more sophisticated Russian surface-to-air missiles (SAMs). According to U.S. military officials, Syria has an air-defense network that is five times as effective as Libya’s, covering one-fifth the territory. Nevertheless, Syria’s air defenses should prove no match for the U.S. and its allies. In 1982, the U.S.-equipped Israeli air force confronted the Syrian air force in the Bekaa Valley and destroyed 87 Russian-made MiG’s and 19 SAM batteries while losing a few helicopters and two aircraft. In 2007, Israeli air units slipped through Syrian air defenses undetected to destroy a suspected nuclear-reactor site without any loss of aircraft.
Even assuming the possibility of more losses over Syria than over Libya or Serbia, the benefits of regime change in Syria would still easily outweigh the costs. Removing the Assad regime would end the ongoing and indiscriminate attacks on civilians and remove a destabilizing agent in the Middle East that has supported terrorism in Iraq, sought conquest in Lebanon and Israel, and served as a vital link between Iran and terrorist groups. International law, properly understood, should allow nations to wage war that benefits global peace and security and preserves civilian life from indiscriminate attack.
There is a chance that events could spiral out of control and lead to a confrontation with Russia and China or regional powers such as Iran. Despite that dire scenario, the probability of a direct conflict remains low. Russia, for example, also opposed the NATO air war in Serbia, where Russia’s strategic and political interests were even stronger, but did not resist. While it might have an interest in increasing the costs of Western intervention by supplying Assad with arms, the Kremlin would gain little by interposing Russian military units against a no-fly zone. Russia is reducing the size of its conventional military, as its budget has fallen along with oil and gas prices; meanwhile, it seeks Western cooperation on strategic-weapons and commodity sales. China also seems highly unlikely to pursue any military response because its foreign policy is rooted in general support for territorial sovereignty against international activism, and the country would have little incentive to risk military confrontation to defend the sovereignty of Syria in the Middle East. Unlike Russia, China does not have the capability to project military power in the region, and it appears to be focusing its current buildup on denying access to the U.S. in the seas around East Asia instead.
While removing the Syrian regime would bring benefits both inside and outside Syria, the aftermath could cancel those gains. An equally or perhaps even more oppressive government could succeed Assad. Or central authority might crumble, causing more civilian death and destruction and the possible dispersion of Syria’s conventional and WMD arsenals beyond its borders. Arguably, the first scenario has developed in post-Mubarak Egypt, while the second may have occurred after the fall of Qaddafi in Libya. The problems of a failed state could replace the threat of a rogue nation. As in Iraq and Afghanistan, the great powers might spend blood and treasure in an attempt to rebuild Syria in the image of a market democracy, which would increase the costs of the use of force and create another obstacle to intervention. Western nations could alternatively allow Syria to devolve into more compact, ethnically homogeneous units that would not require an expensive military occupation and civilian reconstruction. Smaller, more numerous nations would improve the lives of the people living within, and would reduce the threat to the peace of the region without.
Others might calculate these probabilities, costs, and benefits differently. They depend on the prediction of uncertain events and the evaluation of hidden motives and resources. But it seems clear that the real choice is between the improvement to global welfare from a change of regime in Syria and the expected harm of a great-power conflict. Here, the chances of the latter seem too low to veto the modest Western action needed to bring about the former.
— John Yoo is a law professor at the University of California, Berkeley, and a visiting scholar at the American Enterprise Institute. He served in the Bush Justice Department from 2001 to 2003 and is the co-editor of Confronting Terror.