This player was a lot more common in the bad ol’ days of role playing, when the games were still mostly wargames with character rules bolted on. (It’s also one of the reasons why combat rules are usually a chapter long in modern games, but other skill rules fit in a page or two.) Knowing the rules gave you an edge over the dungeon master, with whom you had an adversarial relationship, rather than a cooperative one for telling a story — the DM spent his time coming up with ways to screw with you and your party; you tried to outsmart him. Knowing you got a +1 on a such-and-such test because of certain factors might make the difference between success and a TPK (total party kill, for those not playing D&D.)

The rules lawyer is still alive and well in gaming. Most of the ones I’ve run into are involved in the vampire LARPing scene, where the antagonistic relationship between characters and between the characters and the storyteller remain a central aspect of play. In modern tabletop games, the relationship between the game master/storyteller/dude who’s not a storyteller, but a facilitator for your gaming enjoyment (barf!) is more cooperative, and the rules usually reflect this by being much more minimalist or fluid. This isn’t the environment for a rules lawyering gamer to thrive…but there they are.

Often the rules lawyer now uses the rules to maximize his benefits at character creation, much like the min-maxer, but the rules lawyer focuses on mechanics that allow them to tweak the flow of play to their advantage. So they might take assets (or whatever they’re called in your favored system) like luck, where they can reroll a test, or something like Intuition in Cortex, where they can ask a question of the GM (usually a yes or no question) to skirt the plot.

In modern games where combat is more prevalent, the rules lawyer is much more effective. They know that a certain maneuver allows this benefit, they hang on the wording of a rule regarding social interaction, or how hacking “works”, and use that knowledge to browbeat the GM (or the group, if it’s a GM-less system) into ruling in their favor.

The rules lawyer was, in the past, much more of a nuisance than they tend to be now — but I admit I also don’t play stuff like D&D or Pathfinder where the benefit of lawyering might be more fruitful. In the early days of RPGs, the dungeon master was “god” in his world — and it was almost always a “he” — creating the setting, the adventure, managing the opposition to challenge the players. Rulebooks showed their wargaming past and were packed with minutiae on various tasks. It was hard to know it all well. Rules lawyers could leverage their knowledge of the rules to question the campaign’s architect. Now, it’s expected that the players will have some say in how the plot unfolds outside of succeeding or failing at a test. Plot/hero/story point mechanics allow them to “bribe” the GM to give them a certain result (and vice-versa), rules are less structured and important to the outcome of a scene (FATE can go so far as to go single test for combat with the player stating the preferred outcome), and gamemasters are more likely to working to help the players succeed than to kill their characters off. That makes rules lawyering much less necessary, or effective, than in early generation RPG mechanics.

So how to handle the rules lawyer? You can go with the time-honored “DM as campaign god” with your decisions as inviolate. Or you can set yourself up as a judge or referee, interpreting the rules to the situation — “I know it says the monster gets a -2 for the slippery surface it’s on, but the sheer size means that it doesn’t have to move around as much, so I’m not applying it…” Or you can give the rules lawyer a statute of limitations to argue their point and change the ruling and edit the story. You want to argue a rule that gives you that +1 you need to succeed in stopping the trap from springing? You’ve got a minute to find me the rule, or we move on with events. This gives the rules lawyer — who gets their enjoyment from that argumentation — time to have their fun, maybe have more of an effect on the play, but limits their ability to halt play over some point of procedure.