This morning Iran opened up a plant that produces heavy water, in blunt defiance of UN insistence that it stop its nuclear weapons production activities. They did so just days ahead of an end-of-August deadline imposed by the UN Security Council. Kofi Annan is now en route to Tehran to try to forestall a deepening crisis.

The US’s fellow UN members have in recent years accused us – rightly at times, of sidestepping and denigrating the world body. But if Russia and China do not stand by the UN’s resolution and back up the offer of incentives dangled before Iranian President Ahmadinejad with penalties now that the overture has been rebuffed, it is they – not the US – that will undermine the United Nations. Some months ago, the second highest ranking UN official, Mark Malloch Brown ignited a firestorm when, at a conference sponsored by the Security and Peace Initiative, he laid into the US for failing to adequately back the UN.

If Russia and China back away from concerted and forceful UN action on Iran (I realize I am sidestepping what the nature of such action would be and the questions I raised last night about whether and how sanctions can be made effective, but unity and the perception of forcefulness may ultimately be what matters most here), they will deserve at least equivalent criticism.