Obama faces the conundrum of a system that, as currently constructed, gives the minority party no strategic stake in sensible governance. The two parties are demonstrably different in this respect. Democrats, even in the minority, participate in solutions designed to improve governance. They cannot help themselves.
You can decide for yourself whether you think the rest of Alterman's long essay is useful; I'll simply point out that I'm featuring it as a QOTD and not as a recommendation for the Readings list.