Reusable Defenses Favor the Winner

In any multiplayer game with strong interaction, players will naturally tend to team up against whoever is winning. Such games commonly provide ways to defend against attacks from other players, softening or negating those attacks. Because winners tend to be attacked more frequently and losers tend to be attacked opportunistically, reusable defenses provide more value for winners while limited-use defenses create a free-rider problem that discourages opportunistic attacks against the weak. To understand why, we need to consider the reasons players attack each other, and how different types of defenses affect their incentives.

Since winning players are a threat and losing players are not, players attack winners more frequently than losers. If defenses are reusable, this means that a winner will block more damage with a given defensive resource than a loser will because they will trigger it more times. Therefore, the value of a reusable defense scales with the success of its user. In Oath, the Chancellor starts the game with control of the Longbows card, which they can use in every battle to change the number of attack dice rolled. As the built-in leader of the game, they are likely to see more battles than other players due to others attacking them and will therefore get to use Longbows a lot. A weaker, less threatening player with Longbows would not be attacked as much and would gain less value from it.

When players do attack losers, it is because they want resources those players are too weak to defend. If defenses are limited-use, they create a free-rider problem: removing a loser's only defense means that another rival will have an easier time going after them. In Root, the single-use Armorers card lets a defender ignore all hits rolled against them, negating an entire attack. If you attack a player with Armorers, you will gain no benefit and the next player will swoop in and raze their buildings for points instead. Note that this only disincentivizes opportunistic attacks; if a winner has Armorers, you still want to attack them because the objective is weakening them, so it doesn't matter as much who strikes the final blow.

Defense reusability is a knob with which you can adjust the dynamics of your game between snowballing and rubber-banding. By giving players lots of reusable defenses, you allow leading players to build an impenetrable fortress, closing out their victory. By giving them more defenses that are limited in usage, you discourage attacks against those that are behind, creating opportunities for them to catch up.