One of the first things you learn when attending a political convention is that your value as a human being is directly correlated with the quality of your credential.

In this context, a “credential” is a piece of paper that explains what level of access you have to the convention site. Typically you wear your credential on a lanyard around your neck, so it’s easy for the security guards to see it.

Everybody who wants to enter the convention site has to have a credential of some kind. No credential means no access — which means that, as you approach the convention site, you meet lots of people like the ones in the picture above, who are hoping to find some kind soul with a credential to spare so they can get in and see the show.

So everybody in the convention has a credential — but not all credentials are created equal. There are several levels of credential, each giving progressively more access to the convention site. At this year’s Democratic Convention, the levels are:

• Perimeter, which lets you mill around outside the building, but not get in;
• Arena, which lets you inside the building, but limits you to the lobby areas (in other words, you can’t get into the seating areas where you can see the convention floor);
• Hall, which let you into the seating areas; and
• Floor, which let you onto the convention floor itself, down with the delegates and the VIPs.

(Each level includes all the access of the level below it, so, for example, “Hall” credentials get you everywhere “Arena” and “Perimeter” credentials do.)

As you can imagine, floor credentials are the most coveted, and the hardest to come by. The DNC, understandably, doesn’t want the convention floor getting mobbed with people looking to get a cellphone picture of Barack Obama to decorate their LiveJournal, so they only issue floor credentials to people who have actual business on the floor — people like delegates, whips, press photographers, Members of Congress, and the like. Anyone else who wants to get on the floor has to sign up to use one of a small pool of floor passes the party reserves for general use, and those limit you to only a few minutes on the floor, to keep you from lollygagging.

Or at least, that’s how it’s supposed to work.

The thing about credentials is that they don’t carry any indication of who precisely they were issued to. You get issued a credential, but it doesn’t have your name on it. So anyone who is holding that credential gets the same access to the convention site that you would have if you were holding it.

Combine this fact that everybody wants better access than they currently have and you get a lively new game that’s fun for the whole family: credential-swapping.

Let’s say that I have a Hall credential I’m not using, and you’re a friend of mine, and you only have Perimeter credentials. I give you my unused Hall credential, and now you can get in and watch the show live, rather than on a big video monitor. Meanwhile, I’m trying to find a friend with a Floor credential they can loan me so I can go down and gawk at the politicos on the floor like the rube from the sticks that I am.

Because the credentials get harder to get as their level of access goes up, you rapidly discover that the credential you’re wearing functions as an advertisement of where you are in the pecking order of progressive politics. And since nothing is more American than social climbing, everyone is always on the lookout for an opportunity to trade up.

In that sense, credentials are kind of like Pokémon, only for grown-ups.