Readers of this blog will know that I am skeptical of 44, because I see him as representing the rise of the liberal-tarian left at the expense of liberal institutionalists like myself. In foreign policy, however, Obama has endorsed the institutionalist path, memorably promising during the campaign that he would negotiate with any and all world leaders instead of taking unilateral action and would engage international institutions to combat international problems like climate change.

I had struggled to reconcile this with his professed love of diffuse power. Now I understand: Obama thinks of governance as consensus building amongst individuals. As a result, his vision of international institutions is much the same as his vision of Congress, as a place we go to engage in banter until we arrive at broad and general consensus, rather than as a place for realpolitik dealmaking around concrete specifics.

Predictably, then, his speeches to the UN on climate change and nuclear disarmament were peppered with Kumbaya humanist rhetoric that I found eloquent but banal. I was not alone: his climate speech in particular drew fire from netroots enviro activists who are usually among Obama’s base–it left doors open to all possible approaches to global warming, but tied the administration to none.

Meanwhile, China managed to steal the show even though it flat-out refused to commit to emission reductions. That’s because China did commit to two smaller goals: investments in new forests and reductions in the GROWTH of its emissions relative to its economic expansion. In other words, in dealing with international institutions, it is better to be concrete and incremental (even though you inevitably win some constituencies and lose others by espousing particular policies) than to attempt universal consensus by remaining sweeping and vague. Obama would do well to learn this.

There is a reason that Obama hesitates to commit to any specific goals: he now knows the Waxman-Markey climate bill won’t have passed the Senate in time for his December trip to Copenhagen. Now, it’s a quirk of American governance that while the President signs treaties, he needs subsequent Senate approval for them to come into force. That approval is not guaranteed–indeed, the Senate tends to take pleasure in rejecting treaties that the President signs. As a result, it would have worked better for the President to get the Senate to pass a bill and then use that bill as the limit for any commitment from the US in Copenhagen.

(Why didn’t he do it this way? Because he squandered his summer on the mess that is health care reform, which appears to have fallen apart again. That is despite promising during the campaign to tackle energy first.)

None of this precludes Obama going to Copenhagen, negotiating a deal on his own terms and then bringing it home, trying to get it ratified and to get a domestic climate regulation bill that meets the treaty’s requirements. Except that international observers are now savvy to the workings of the US government–as a result, Obama’s ability to negotiate a deal with foreign leaders is diminished because they aren’t sure if a piece of paper Obama signs will get the full force of his government’s approval. (Beyond climate policy, this strikes me as a huge structural problem for American diplomacy.)

As a result, knowing that they will be traveling to Copenhagen sans legislative backing, the administration is trying to drum down expectations for any comprehensive climate deal, and instead focusing on bilateral incremental tweaks. Here’s the problem: on any other policy issue, if you fail to get a big systemic change, you are left with a lousy status quo. But with Kyoto set to expire, a failure in Copenhagen means no status quo at all. As in, environmental policy just ceases to exist.

To me, it comes back to Obama’s governing style. His inability to manipulate the Congress feeds his inability to make firm international commitments. In a cruel and ironic twist, it all conspires to undermine the one thing I thought Obama would be good at–restoring our involvement and our prestige in the international community.