Russia's Syria chemical weapons proposal is welcome, in principle Co-operation on Syria would benefit all - we should examine the details, writes Ivo Daalder The last-ditch effort by Moscow to avert a US strike against Syria - proposing Damascus signs up to the global ban on chemical weapons and puts its chemical stockpile under international controls - has merit and is worth pursuing. It also demonstrates that the threat of using even limited force can have real utility, and that a speedy congressional vote backing President Barack Obama on strikes remains necessary. When the first reports of the deadly poison gas attack emerged from Damascus three weeks ago, the issue of military action took an important turn. Up to that point, the Obama administration had steadfastly - and rightly - resisted calls to intervene militarily in the increasingly bloody civil war. Not only did the president confront a war-weary public that had absolutely no interest in becoming entangled in another Middle Eastern conflict, but he had also long concluded that doing so would make this his war - and ending the conflict his responsibility. He rightly held back. Yet the use of poison gas by the regime of Bashar al-Assad made it impossible to stand aside any longer. Mr Obama had drawn a red line 12 months earlier, when he declared that the use of chemical weapons would change his calculus on the use of force. The use of these weapons also represented a moral and strategic affront to the world. For almost a century, the use of chemical weapons has been an international taboo. They were banned by the Geneva Protocol of 1925, negotiated as a result of widespread revulsion at the large-scale deployment of chemical agents in the first world war. Though ruthless dictators would at times resort to using poison gas - including Benito Mussolini in Abyssinia in the 1930s and Egypt's Gamal Abdel Nasser in Yemen in the 1960s - it was not until the Iran-Iraq war in the 1980s that chemical weapons would again be used on a large scale. This, coupled with the gassing of Kurdish civilians by Saddam Hussein in 1988, reinforced international efforts to ban not just the use of chemical weapons, but also their production and possession. These efforts succeeded in 1993, with the conclusion of the chemical weapons convention, which has now been signed by all but five countries. Syria, unfortunately, is one of the five. And it is Syria that has now become the first country actually to use chemical weapons since the convention went into force. Mr Obama has rightly insisted that there must be a firm response to Syria's breaking of this well-established taboo - a military strike that would punish the Assad regime, degrade its ability to launch further strikes, and deter it and others from resorting to chemical weapons use in future. In the past week, the administration has won more international support for a decisive response - including from a majority of countries attending the summit of the Group of 20 leading nations in St Petersburg, and from EU and Arab League foreign ministers at the weekend. The growing sense that the Syrian regime's gassing of its own people cannot be allowed to stand no doubt motivated Moscow to float the idea of Damascus signing the chemical weapons convention, placing its storage sites under international control and destroying all weapons stocks. More than anything else, such an outcome would reinforce the international norm against chemical weapons. It would be much preferable to the alternative of having to use force. But the details will matter. Getting international inspectors into Syria will require either massive armed protection or an end to the raging conflict - neither of which is likely any time soon. And, so long as the weapons remain under the regime's control, their use remains a distinct possibility. Of course, the same would be true following the kind of limited strike the administration has contemplated. Nevertheless, Moscow's idea is worth pursuing. Persuading Russia to co-operate in getting rid of Syrian chemical weapons is in everyone's interest. If the end result is a Syria with no chemical weapons, the world will be better off. We need to examine the details of the plan, and to establish a very clear timeline - days or weeks, not months - to gaining Damascus" full agreement on such a plan. In the meantime, it is critical to keep the pressure on Syria - including the threat of air strikes backed by a strong, affirmative vote by Congress. The very real prospects of these strikes seems to have brought Moscow around. Continuing the credible threat of force may do the same with Damascus - to the benefit of all. The writer, US ambassador to Nato 2009-13, is president of The Chicago Council on Global Affairs