The path to where the U.S., Russia, and Syria are now — with an initial US/Russia agreement on a plan for disarmament of Assad’s chemical arsenal, to be put before the UNSC — has been idiosyncratic to the point of good comedy. But where they have ended up should be starting to look familiar, and arguably tells us something about the structure of post-Cold War international politics.
Way back in 2001 the Monkey Cage’s very own Erik Voeten published an article (gated) in the American Political Science Review called “Outside Options and the Logic of Security Council Action.” He noted the large increase in multilateral cooperation through the UNSC after the end of the Cold War. For example, between 1990 and 1998 the UNSC approved 31 peacekeeping operations (PKOs) and passed 145 resolutions under Chapter VII (which can authorize use of force). By contrast, from 1945 to 1989 there had been only 15 PKOs and 22 resolutions under Chapter VII. One major, relevant change was that the veto has been exercised much less often.
During the Cold War, veto threats by either side came along with the implicit understanding that acting unilaterally could lead to a dangerous escalation between the US and the USSR. With the collapse of the USSR, all kinds of US threats to intervene — often against regimes it doesn’t like for one reason or another — have become more credible. However, the US, the rest of the Permanent Five on the UNSC, and a lot of other countries all would, in general, prefer that US or US-led military interventions be approved and sanctioned by the UNSC. The other veto players, and especially Russia, want to be able to constrain and influence US use of force. US administrations, on the other side, want formal authorization because they correctly see this as reducing the costs of intervention and also as a way to increase domestic support from an intervention-averse US public.
Voeten’s article observes that this configuration of preferences, capabilities, and the institution of the UNSC sets up a typical bargaining situation: The US and the rest of the P5 both have reasons to want an intervention, should it happen, to go through the Security Council, but they always have conflicting preferences over the terms. In many cases, of course, Russia would strongly prefer no intervention at all, but at least a deal in the UNSC preserves the apparent authority of the institution, where Russia still has the symbolically important veto. According to Dmitri Trenin, this is an important consideration for Putin in the current crisis.
Multilateral cooperation through the UNSC thus often take the form of the US, sometimes with allies, threatening to intervene without UNSC authorization. This is the “outside option,” and it stands behind negotiations over whether there are terms for a UN resolution that both the US and the “constrainers” would both prefer to its exercise. Usually this leads to intervention or multilateral action with UNSC authorization, as in Bosnia or Haiti. But sometimes not, as in Kosovo or Iraq. So the way this episode with Syria is playing out has basically happened before, and there are good reasons to expect that it will happen again, sooner or later.