One way of promoting player vs. player interaction would be to introduce an "Opposing Outcome" Challenge Card. Unlike conventional challenge cards (with strong or weak outcomes), an Opposing Outcome Challenge would be used by players to determine which of two mutually exclusive outcomes take place. The accompanying image shows what two of these cards might look like.

The challenge presents two alternative Courses Of Action. These COA’s might be in the form of two choices (administer conventional medicine or an untested experimental vaccine in a medical game; reason with a creature/monster or attack it in a sci-fi/fantasy game; voting for or against impeachment in a political game, etc.) Instead of just one set of boxes which tallies the strength/weakness/asset cards the players use, the challenge has two sets of boxes—one for each alternative COA. Once the characters have played their cards, the COA with the strongest outcome prevails.

Mechanics:
Once a player uses a card for a given COA, he/she can NOT play a card against the alternative COA (should be restricted from doing so by the gaming software). This prevents a player for playing a strength card against one COA and then playing a weakness card against the opposing COA (in effect sabotaging the alternate outcome).

2. A positive card is worth +1, a negative card is worth -1; asset/goal/subplot cards (nominally considered neutral under the current system) are worth +0.25.

3. Although both outcomes might be positive overall, the COA with the highest net “score” wins. (Example: Players favoring COA-A expend a strength card and two (neutral) asset cards for a net score of +1.5. Players favoring COA-B expend two strength cards and one asset/goal/subplot card for a net score of +2.25, thus winning the challenge)

If the two Outcomes receive numerically identical scores, the technical result is an uncertain outcome, though the types of cards played and the strength of the accompanying posts may still allow the Narrator to declare that a particular COA appears to have the upper hand.

Game Play Implications:

This type of card would allow characters to work together in most situations (as they do now in Storium), but would allow the Narrator to force them to perhaps work at cross-purposes (or perhaps in direct opposition to one another) at certain critical points when an Opposing Challenge Card is introduced in a story. It would also allow for the Narrator to set up a “Faction vs. Faction” style of play when designing a game (Loyalists vs. Rebels; Abolitionists vs. Slave Owners; Vampires vs. Werewolves, Hatfields vs. McCoys, etc.). Players might find themselves holding their strength cards in reserve for use in some future potential challenge rather than expending them willy-nilly (how many times have we seen a player use a “Charismatic Leader” strength card in the largely throw-away “getting to know you” challenge of a first scene??). At some point in the game, one faction/player may find that they are in possession of only weakness cards and may realize that they are in a really bad situation when that critical Opposing Challenge finally manifests itself.

Of course, there will be times when all the players are in substantial agreement on an important decision. In that situation, the Narrator might find that all the squares for “Outcome A” are filled with strength cards, but nobody is interested in supporting “Outcome B” with its still empty squares. In that situation, the Narrator has still given the group to opportunity to choose between two distinct courses of action, and they have done so. At that point the Narrator should end the scene and move on in the new direction indicated, even though there are still empty squares remaining for the second outcome. As noted above, in the case of “tied scores,” the Narrator would still have leeway to declare a given outcome based on the types of cards played and the quality of the player posts accompanying each COA being supported.