Obama's rocky path...
And the UN is back at center stage, as a rules-based international order demands that it should be on such issues, with both its weapons inspectors and the Security Council regarded as central to future developments.
Yes, there were some things that could and should have been done differently. There always are. If the justified intervention in Libya by the US, the UK, and France had not later been conducted with such clotheared indifference to Russian, Chinese, and developing-country concern about mandate overreach, greater unity on Syria could have been achieved in the Security Council in 2011, when a united message might have stopped Assad cold.
Going to Congress for approval was always going to involve more risks than rewards. Secretary of State John Kerry's description of the planned US military response to the Ghouta massacre as likely to be "unbelievably small" almost derailed the utility of the US threat in concentrating Syrian and Russian officials' minds.
And the administration could have helped itself by better explaining that a cooperative response to the Assad regime's use of chemical weapons had long been on the table, and was not just the result of deftly opportunistic Russian diplomacy in response to a Kerry thought-bubble.
What has trumped these missteps, and enabled each side to focus on opportunities rather than excuses, is that both the US and Russia now understand that they have common interests in Syria. Both sides want not only to preclude the Assad regime's further use of chemical weapons, but also to find a route to sustainable peace in Syria, and to reestablish the authority and utility of the UN in these situations.
Of course, optimism must be tempered. Plenty can go wrong in the period ahead. Either a beleaguered Assad or an increasingly desperate opposition might destroy the deal on the ground. The fragile rapprochement between the US and Russia may not hold, particularly if the US again insists - breaking its recent helpful silence - that Assad has no place at the negotiating table.
But when the major powers cooperate in a just cause, the world is a safer and saner place. That is where both the US and Russia - and on this issue China as well - want to be. If Obama's caution and flexibility have been the key to getting us here, let us give praise where it is due.
Gareth Evans a former Australian foreign minister and president of the International Crisis Group, has been Chancellor of The Australian National University since 2010. He chairs the New York-based Global Center for the Responsibility to Protect.
Copyright: Project Syndicate, 2013.
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