Ezra Klein put a clarification, of sorts, up on his blog regarding his claim that the constitution is too old and confusing to be taken seriously - although he doesn't understand why anyone was confused.

The initial interpretation was that I’d said the Constitution is too complicated to understand because it was written a long time ago, and then, as the day went on, that I’d said the document itself is nonbinding. I went back and watched the clip — or at least the part someone clipped and sent me, which is above — and thought I was clear enough. But when a lot of people misunderstand you at once, the fault is usually yours.

So if I was unclear: Yes, the Constitution is binding.  No, it’s not clear which interpretation of the Constitution the Supreme  Court will declare binding at any given moment. And no, reading the  document on the floor of the House will not make the country more like  you want it to be, unless your problem with the country is that you  thought the Constitution should be read aloud on the floor of the House  more frequently. In which case, well, you're in luck!