Gideon Rachman of the FT has a provocative (well, for me anyway) post on his blog:
The essence of the 'irrelevance' claim is that Obama hasn't hired any political scientists to important jobs, whilst economists - despite their embarrassing failure to predict the (economic) end of the world - still have marketable expertise.
There are any number of explanations for this lack of prestige as a profession, but one - proferred by the late lamented Brian Barry - is that politicians tend to see themselves as the real experts on politics, rather than as the raw material political scientists study. I have a feeling he was right - whilst Obama will doubtless take economic policy decisions on the basis of extensive briefings by professional economists, he probably feels confident that he knows politics better than most poli sci professors. And having just landed the biggest job in politics, who can blame him?
I'm not sure policy advice is really such a measure of relevance in the end. We have a few workable theories that are of some use in designing some policies and institutions, but for the most part we - like the economists, but with a bit of humility - are constantly chasing the curve, trying to make sense of things that have just happened.
Is this because we are useless, or because life is unpredictable? Probably both. As a neo-Talebite, I go for the latter. People may behave in predictable ways a lot of the time, but every now and again do the unexpected, like vote for Obama, for example. Or start believing en masse that a piece of brick on a piece of earth will grow in value even when nothing else does. And those unpredictable events, though perhaps exceptional, end up changing the world in such big ways that they cannot be dismissed as outliers.
So Obama can probably do without us, but when something happens that he wasn't expecting, we'll be sitting there ready to explain it afterwards.