We’ve all heard of the all-important superdelegates. I’ve even talked to two of them from Washington State - Pat Notter, who long ago declared her support for Obama, and David McDonald, who remains uncommitted.

We know there are about 800 of them, and they are typically Democratic officeholders or party officials. We know they could very well decide the Democratic nomination. And we know the pressure to declare their support for Clinton or Obama has increased even more since Clinton’s Pennsylvania win.

So what don’t we know? I recently came across a news article that explored a rarely-discussed fact about superdelegates: that some superdelegates are more “super” than others. This means that, in addition to the conventional superdelegates (party leaders, etc.), 76 unpledged add-on delegates are chosen by state party chairs, state party conventions or committee meetings throughout the spring.

Some of those unpledged add-on delegates have been chosen. Many haven’t. So when the media refers to “undecided superdelegates,” they’re looking over one small detail: we don’t even know who some superdelegates are yet.

What does this mean for Washington State? For Clinton? For Obama? For the fate of the nomination? I’ll answer all these questions and more in a longer piece I’m working on about the unpledged add-ons.

Until then, I’ll leave you with some more fun superdelegate facts:

- The number of superdelegates and unpledged add-ons can change (and has already changed).
- There are currently slots for 76 unpledged add-ons, with an additional total of 5 from Michigan and Florida if the states’ delegates are seated.
- Other reasons the overall superdelegate count has depleted: California Rep. Tom Lantos died in February; former Maine governor Kenneth Curtis moved to Florida and lost his superdelegate vote; New York governor Eliot Spitzer resigned and lost his vote (the new governor, David Paterson, was already a superdelegate anyway).
- The current superdelegate count, including unpledged add-ons, is 794. This could change to 795 if a Democrat fills Lantos’s California seat.