The news of the day, as I mentioned earlier, is that Richard Shelby has decided to place a hold on everything that eats, breathes or moves unless Alabama gets a couple billion more in pork. Before we take a step further on this, it's worth noting that Shelby is doing exactly what Ben Nelson did, but attaching a larger price tag to his demands: He's threatening to obstruct Senate business unless his state gets billions in giveaways. Nelson settled for hundreds of millions. Nebraskans must be pissed.

But put all that aside: Shelby is putting a "hold" on all of Barack Obama's pending nominees. So, uh, what's a hold?

The first thing to understand is that there's no such procedural move as a "hold." It's not something senators have in their special senatorial utility belts. Instead, a "hold" is shorthand for a promise to obstruct all further consideration of a particular piece of Senate business.

The best explanation of how this works came from David Waldman, and I encourage you to read it in full. But here's the short version: The Senate generally uses unanimous consent agreements to set the rules for a bill or a nomination. A hold, in its simplest form, is a promise to object to unanimous consent...

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