Securing Syria's stockpile of chemical weapons as a first step toward destroying them would be neither a short nor an easy process, and it could require a halt to the fighting to allow inspections.
"These kind of disarmament agreements require a very intrusive inspection system; the natural assumption is Assad will cheat," said Gary Samore, President Barack Obama's former coordinator for arms control and weapons of mass destruction. "I just don't know how you can have that kind of inspection system in the middle of a civil war."
Getting President Bashar Assad to turn over his chemical weapons to international monitors has emerged as an alternative to a potential American military strike. Russia seized on comments by Secretary of State John Kerry, who raised the idea as one way to resolve the standoff, and Syria agreed to the Russian proposal.
The United States, Britain and France will consult with Russia and China on a United Nations Security Council resolution "requiring Assad to give up his chemical weapons and to ultimately destroy them under international control," Obama said Tuesday night in a televised White House speech. Any accord must verify that Syria keeps its promises, he said.
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The U.S. is still eliminating its own stock of chemical weapons, showing that getting rid of Syria's arsenal is likely to take several years, Sen. Bob Corker, R-Tenn., said Wednesday.
"We still are destroying the ones that we have," Corker, the top Republican on the Senate Foreign Relations Committee, told CNBC's Squawk Box program. "It would take decades to do away with the chemical weapons in the appropriate way."
The U.S., which joined the Chemical Weapons Convention in 1997, has failed to eliminate its stocks within the 15-year deadline set by the agreement, according to a paper titled, "Indisputable Violations: What Happens When the United States Unambiguously Breaches a Treaty?" by David Koplow, a professor at Georgetown University in Washington.
The U.S. removed about 90 percent of its stockpile by the April 29, 2012, deadline and will take until 2023 to destroy the rest, Koplow wrote. Russia got rid of 60 percent of its stock by the deadline and expects to complete the rest by 2015, he wrote.
The U.S. "has neither contested its prima facie failure to meet" the deadline "nor advanced any defense against the legal conclusion," Koplow wrote.
Before any inspections could begin, Assad would have to sign the Chemical Weapons Convention prohibiting their production and possession and requiring the destruction of a country's stockpile on an agreed-upon schedule. Syria would then have to produce a detailed description of its arsenal and a team of international inspectors would verify that the accounting was complete and accurate and begin securing the chemicals.
Just gaining access for those inspectors may require negotiations. Assad's regime agreed to allow U.N. inspectors to probe the alleged use last month of chemical weapons only if they guaranteed that their final report wouldn't identify who was responsible, two U.N. diplomats from different Security Council member states told Bloomberg News. Both asked not to be named because of the sensitivity of the matter.
The Assad regime insisted on this in negotiations with U.N. disarmament chief Angela Kane, said the diplomats. U.N. spokesman Farhan Haq said the investigation's mandate, which doesn't require the world body to establish culpability, dates to the Iran-Iraq war in the 1980s and in the cases of Azerbaijan and Mozambique in 1992, where the use of chemical weapons was suspected, and isn't unique to the Syrian situation.
U.S. officials "are working on exactly what would be required" to take control of Syria's arsenal, Kerry told lawmakers Tuesday.
Syria may have about "1,000 metric tons of numerous chemical agents, binary components, including finished sulfur, mustard, binary components for sarin and VX," Kerry said. "Most of that is in the form of unmixed binary components, probably stored mostly in tanks. But they also possess sarin- filled munitions and other things," he said.
How quickly the chemical weapons could be secured will depend on how many locations are involved, Jean Pascal Zanders, an expert on chemical, biological and nuclear-weapons disarmament, said in a phone interview from Ferney-Voltaire, France. "If they can be located in as few places as possible, then it becomes easier to guard these stockpiles."
The U.S. and its allies have identified more than 40 Syrian chemical-weapons manufacturing and storage facilities yet located fewer than half of them, said a U.S. official who asked for anonymity to discuss intelligence matters. The problem of targeting or securing them, the official said, is compounded because the evidence suggests the Syrians almost constantly have been moving the weapons and the units that control them.
Even with the challenges, Samore, who left the White House earlier this year, said if he were still advising the president he would recommend that Obama accept the offer if it included U.N. sanctions to authorize military force against Syria for non- compliance. A disarmament program would do more than a strike to reduce the likelihood that Syria's chemical weapons would be transferred to terrorists, he said.
Still, trying to carry out inspections and securing chemical weapons amid a war is "kind of an unprecedented situation," said Daryl Kimball, executive director of the Arms Control Association in Washington, in a telephone interview.
It could take weeks or months for inspectors from the Organization for the Prohibition of Chemical Weapons, or a U.N. team to verify a Syrian declaration of its stockpile, and their safety may be difficult to secure given the conditions on the ground, Kimball said.
"Even if Bashar al-Assad's regime cooperated with chemical weapons (CW) inspectors, locating and gaining access to Syria's CW amid a civil war, in which control of territory is contested by a variety of armed groups and Damascus's authority is limited, would be near impossible, and destroying those CW would take a long time," Michael Singh of the Washington Institute for Near East Policy wrote on the Foreign Policy magazine website Tuesday.
Once inspections were completed and all Syria's chemical weapons were secured, under normal circumstances, the chemical agents would be incinerated or neutralized either on sites built there or moved elsewhere for destruction, Kimball said.
Inspectors could deploy mobile incinerators to where the "munitions are stored and can be destroyed there," said Zanders, who runs a consulting group called The Trench and was previously an analyst at the European Union Institute for Security Studies.
If the chemicals are stored in bulk containers or in binary forms — with the precursor chemicals stored separately — destroying them would be easier than if the chemicals were already placed in munitions that must be drained, Zanders said.
Given the civil war in Syria, destruction of the chemicals might have to wait until the conflict is over, Kimball said. As a result, international observers would need to keep the sites and stockpiles "under lock and key" with measures to secure the facilities until the destruction schedule could begin, Kimball said.
In the case of Iraq, it took the U.N. two years to verify and destroy the country's chemical weapons' arsenal, said Amy Smithson, a fellow at the James Martin Center for Nonproliferation Studies in Washington. "This would be a long, drawn-out process, and given Assad's track record I'd place great skepticism," she said.
Even with the hurdles, the limited U.S. goal of deterring Assad from using chemical weapons could be achieved if Russia is able to reach agreement with Syria, said George Perkovich, a nonproliferation expert at the Carnegie Endowment for International Peace in Washington.
An accord between Russia and Syria "itself would go a tremendous way to get the deterrent," Perkovich said in a phone interview. Such an agreement would signal to Assad that the U.S. and Western Europe aren't alone in opposing the regime's use of chemical weapons, he said.
Iranian President Hassan Rohani, who has condemned the use of chemical weapons, could also press Assad to come to terms with Russia, making such a deal "not worse than other options" including a U.S. military strike, Perkovich said.
Still, Russia's interest in keeping Assad in power can't be underestimated, Smithson said. Russia is the main supplier of conventional arms to the Syrian regime.
"As long as Assad stays in place, Moscow makes money," Smithson said.
With assistance from Mike Dorning in Washington and Sangwon Yoon at the United Nations.