{{#evt: | service= youtube | id= SMJK0w2Pkng | description= Victoria 3: November 2021 Update. A summary of last month's dev diaries, including: Rank and Prestige, Relations, Infamy and Interests, Diplomatic Actions, and Diplomatic Plays. | alignment= right | container=frame }}
外交机制包含三个基本要素：关系、恶名与利益。
关系
关系是一个介于 -100与 +100之间，展现两个国家宏观外交立场的数值。维多利亚3中的外交关系系统是双向的，即两个国家的外交关系总是由一个数值衡量，而非其他游戏中单向关系。这一系统清楚地衡量了两国对对方的外交立场，这一机制性效果将同时作用于AI和玩家（即使是在多人游戏中）。
所有外交关系数值将会转换为一个关系等级，达到不同等级所需的数值列在下表（从高到低）：
亲密 (80 - 100)
善意 (50 - 79)
合作 (20 - 49)
中立 (-19 - 19)
较差 (-20 - -49)
冷漠 (-50 - -79)
敌对 (-80 - -100)
外交关系的作用
外交关系等级将会影响AI是否接受外交提议以及在外交博弈中支持哪一方。此外，达到不同外交等级也将允许/禁止对该国家发起特定外交行动。
例如，达到 合作或以上的外交关系等级后将禁止两国对对方发起绝大部分的外交博弈，几乎可被视为一种互不侵犯条约。同时，邀请他国进入关税同盟也需要两国关系等级至少达到合作。另一方面，进行特定敌对外交行动，如禁运、宣告宿敌等则需要两国关系低于特定等级。
改变关系等级
改变外交关系最直接的方式就是使用改善/破坏关系外交行动，但也存在其他手段。这些手段包括但不限于触发事件、外交事件以及驱逐外交官（该方式能够一次性破坏两国关系，且在短期内杜绝改善关系的可能，有助于将两国关系维持在较低水平以便发起后续行动，但驱逐外交官也将受到恶名惩罚）。
恶名
每个国家的初始恶名都为0，最高可达到 1000。当一个国家的恶名上升时，其他国家会对该国更加警惕，并使得产生恶名的国家受到一系列外交惩罚。如果恶名突破了 100，其他列强将能对该国发起特殊外交博弈以清除其对国际社会的威胁。
恶名将随时间缓慢衰减，且其速率与该国未使用的外交影响力挂钩，象征着该国投入多少外交努力来消除其造成的不良影响，恢复其名誉。
恶名系统也可反映列强们对一个国家的关注程度，国家地位将会影响一国发起侵略性行为时产生的恶名。总体来说，博弈双方的国家地位越低，其产生的恶名越少。列强们更加关心其他列强的行动而不是两个边缘小国的斗争。
此外，产生恶名的地区也值得关注。如果在一个战略区域产生大量恶名，严重破坏该地区的和平稳定，产生恶名的国家与所有在该地区拥有利益的其他国家的关系都会恶化。
外交事件
恶名系统与外交事件系统绑定。在大多数情况下，一个国家采取了会产生恶名的行动后（如征服他国领土）将会在对应战略地区触发外交事件。
例如，在西非地区发起夺取殖民地的外交博弈将会在该地区导致外交事件发生。一旦外交事件发生，所有在该地区拥有利益的国家与发起国的外交关系都会立刻降低，降低的数值取决于产生的恶名数值。
恶名等级
0 to 24,9 - Reputable
25 to 49.9 - Infamous
50 to 100 - Notorious
>100 - Pariah
利益
Interests is a mechanic that determines whether or not a country has a stake in a particular strategic region and plays into numerous different mechanics such as diplomatic plays, colonization and the aforementioned diplomatic incidents.
Interests do not provide any inherent benefit to a country besides the ability to throw their weight around in a strategic region, and can actually be a bit of a double-edged sword in that a country with interests all over the world may get dragged into a lot of local conflicts. Ultimately, interests are intended to simulate such historical occurrences as why certain parts of the world simply got a lot more attention from the great powers than others at particular points during the century that Victoria 3 covers, and to make nations act and care about things in a way that makes sense according to their national self-interest.
A country can gain an interest in a region in one of two ways: either automatically by having a geographical presence there (owning land or controlling subject nations in the region) or by using a declared interest.
宣告利益
A declared interest is a country quite simply saying that, regardless of their lack of a geographic presence, a strategic region is still of importance to them, perhaps because they plan to colonize it, or because they want to prevent a hated rival from expanding into it. A country can declare an interest in any region that is either adjacent to a region where they already have an interest, or which they can reach through the support of their naval supply network. The number of declared interests that is available to a country depends on their rank - a great power can choose to have its fingers in a great many pies, while an insignificant power is limited to acting only in regions where they already have land.
可宣告利益数量
A country may declare as many interests as its Maximum Declared Interests cap. This cap is determined by ranking, and the presence of Naval Bases in the country.
修正
| 来源 | |
|---|---|
| +5.0 | being a Great power |
| +3.0 | being a Major power |
| +1.0 | being a Minor power |
| +0.1 / level |  Naval Base with the  Man O' War production method (Rounded down)
|
| +0.12 / level | Naval Base with the  Ironclad production method (Rounded down)
|
| +0.15 / level | Naval Base with the  Monitor production method (Rounded down)
|
| +0.17 / level | Naval Base with the  Dreadnought production method (Rounded down)
|
| +0.2 / level | Naval Base with the  Battleship production method (Rounded down)
|