I was thinking about modifying my previous D&D social encounter system to be more analoguous with combat. Here goes.
The “argumentation” happens in a grid, like combat. There are some squares that cannot be moved into, representing covered angles. This is referred to as the Field. Both parties appear in their own groups in opposing corners. Movement in the Field happens as in combat: Speeds, diagonal movement and so on. Everyone takes their turn in initiative order.
Instead of attacking with normal attacks, however, the players use their skills against the opponents’ defence values. Armor Class is not used. Diplomacy goes against Will, as it takes focus to see proper arguments amidst empty rethoric. Intimidation goes against Fortitude, as only the steel-hearted can stand against fear. Bluff goes against Reflex, as one must be careful to navigate the minefield of lies. If one wishes for the system to make more sense, they can create their own Social Defences to use. If the players want to use other skills, the DM can treat them as special actions, as described on the DM Guide. Hit points are used normally. They represent how long the person can come up with new angles and explanations. Damage taxes one’s ability to do that. The amount of damage an attack does is determined by the DM, using the Damage By Level table on the DM Guide. A nonspecific objection does not carry a lot of weight, so it would use low normal damage expression. A fact-supported argument would be usable only once, so it would use Limited Damage Expression. I would perhaps rule that high skills do low damage and low skills high damage, because it would enable the players to take risks. Would I try to do maximum damage with Dungeoneering, or just nibble the enemy to death with my diplomatic prowess?
When a player’s hit points go to zero, he or she loses credibility in the conversation, and no-one listens to him or her anymore. The player will drop from the field. Note that there is no “death” saving throw, mainly because the character won’t die as a result (probably). The only way to regain HP is by using Second Wind.
In addition to knocking every opponent down, there is an alternative way to win an argument: By attacking the opponent’s position. This position can manifest as an area on the Field, like a 3×3 grid on top of a “tower”, or as a metaphoric ball that an opponent possesses. By knocking all opponents away from the position or by knocking the bearer of the “ball” down, the players can ruin the oppositions point, winning the argument. The DM is encouraged to modify these ideas as he or she wishes.
The mechanic would fit large negotiations with multiple opponents nicely as a replacement for the normal skill challenge mechanic. I imagine this is too heavy to use constantly, though, so in cases where a single opponent stands in the way or if one side is clearly in a better negotiating position (a sword at the throat), normal dice-rolling should suffice. I just like the idea of having a metaphorical battle of wits as a game mechanic to handle exciting social situations.