Things have clearly gotten out of hand, as this latest news demonstrates. The Annan Plan was at most a speed bump, already crossed by both sides, and it's fairly clear that pieces of paper and declarations aren't going to constrain the actions of either Assad or the Syrian opposition forces arrayed against him. It's a civil war, or about to become so (depending on your definition), which can only end in victory for one side or prolonged bloody stalemate that eventually brings both to the bargaining table.
In the meantime, as the civilian death toll rises the rest of the world wrings its hands and tries to decide whether to intervene or not. Concerns about Syria becoming a proxy conflict for much of the region are real, although so long as the conflict actually stays within Syria (and maybe Lebanon) I suspect that everybody else is basically OK with that. The pressure in the West is mostly humanitarian - a variant on the Peter Parker problem ("With great power comes great responsibility"). Or, as it might be most basically expressed, "how can we stand by with all those innocent people dying?"
The problem is that the current phase of the international dance involves the US (and some Western allies) trying to use the UN system to fashion some kind of international collective action. That's a great idea, except that we already broke the UN system for that purpose, and we can't just put it back together by fiat now because it happens to suit us. Here's a good quote from the above article:
The U.S. envoy to the United Nations warned that unless the Security Council acts swiftly to pressure Syria to end its crackdown on opposition, countries may act outside of the world body.This kind of warning is at best worthless, and at worst hypocritical. What has the US done the last two times (Iraq, Lybia) it decided it needed to use force to alter a country's internal politics? Did we ask for the Security Council's OK? Notice that these two cases came under two different presidents of different parties - a point not lost on the rest of the world, even if we insist that there are somehow radical differences between our political factions.
The US has already made it clear that it will act unilaterally when it thinks it is in its interest to do so. Realists will cheer this as clear-headed thinking, and there's certainly an argument to be made there. But you can't have it both ways. If the US is free to do what it wants, when it wants, then the notion of the UN Charter as a voluntary set of restrictions on freedom of action is dead. What the US claims as its right, everyone else will too. The rest of the world doesn't buy the "we're the world's only superpower, so we get to do things no one else does" argument.
So in the case of Syria, waltzing around the UN is simply a waste of time. Even if the Obama administration wants to restore the UN Security Council system to credibility, it's too late - that system is dead, with the last few nails driven in the coffin by its own actions in Libya. And since we've remade the world in the Realist image, the only questions now are: what is in US interest? What do we have the capability to do? What will other powerful players likely do in response, and what is the approximate balance of power surrounding this issue? Hopefully, US policymakers - having abandoned many of the structures set up after World War II - can at least think through this much before rushing into unwise actions.