When playing using A House Divided or Heart of Darkness, war justifications are required in order to declare war against your many opponents. The process for creating casus belli and executing them in your strategy are outlined below.
Justification of war will cause you to gain infamy almost every time, and care needs to be taken to avoid going over your infamy limit. The longer a nation's attempt to justify the war goes undetected, the lower the infamy gained from the justification will be. The relationship between time and infamy is direct, so being discovered halfway through the process leads to gaining half of the infamy.
A CB may also be gained by an event. Several different casus belli can be gained this way, but it is the only way to gain the repay debts CB.
Each CB comes with a war goal. Declaring war using a CB automatically adds that goal to the war; other CBs against the same target let you add their goals without gaining infamy. Achieving a war goal brings prestige to your nation. Prestige gain is always a percentage of your target's prestige, with a minimum of what you would gain from defeating a 100-prestige nation. Failing to achieve a war goal will result in a loss of 10% of your prestige.
Each war goal will cost a certain amount of war score to demand when proposing a peace treaty; some of these quantities are fixed, while those relating to acquiring or giving up territory vary depending on the value of the territory. The cost of a war goal is only a guideline, however: usually a nation will require you to have accrued more war score than the cost of your war goals to capitulate. A nation will never accept a peace deal with a cost above 100.
To add a second war goal in a war, a certain proportion of the country's population must support jingoism. Adding one makes 25% of your pops that support jingoism support pro military instead, so war goals cannot be added indefinitely. It also incurs infamy, the amount being the same as the maximum possible for justifying such a war (for example, adding Acquire State costs 11 infamy). What causes pops to support jingoism varies by occupation, but the most important is being at war with low (less than 5) war exhaustion.
CBs in Heart of Darkness
|Action||Time||Maximum Infamy||War Score Cost||Prestige Gain||Requirements||Effects on Loser|
|Acquire State||400 days||+11||Varies||4%||Both nations must be either civilized or uncivilized||Cede selected territory to victor.|
|Conquest||400 days||+22||85||10%||Single state nations, or uncivilized nations with 4 or fewer states||Annexed by victor.|
|Place in the Sun||200 days||+10||Varies||4%||Target owns colonial states||Cede selected colony to victor.|
|Cut Down to Size||200 days||+13||50||10%||none||Loses 50% of its current armies, cannot build ships or train brigades for five years, gives 25% of its tax income to victor for five years.|
|Free People||200 days||+7.5||Varies||2%||Target has cores of another nation that can be released||Cede selected state to nation.|
|Liberate Country||200 days||+11||Varies||2%||Target has cores of another nation that can be released||Give up cores on all territory also held as cores by other nation, and cede that territory to them.|
|Humiliate||200 days||+3||15||5%||none||Lose 25 prestige, plus 10% of current prestige.|
|Make Puppet||200 days||+10||85||5%||Target is not a Great Power or subject nation, has three or fewer states||Become a satellite of the victor.|
|Release Puppet||200 days||+2.5||30||10%||Target has at least one satellite||Satellite nation is freed and joins victor's sphere of influence if the victor is a great power|
|Add to Sphere||200 days||+4||50||10%||Aggressor must be a Great Power, Target is not a Great Power||Become part of victor's sphere of influence.|
|Take from Sphere of Influence||200 days||+4||20||15%||Aggressor must be a Great Power, target must be a Great Power, target has at least one nation sphered||Selected nation joins victor's sphere of influence.|
|Demand Concession||166 days||+5||Varies||0.2%||Must be civilized. Target must be uncivilized and have more than one state.||Cede selected territory (not the capital state) as colony.|
|Establish Protectorate||166 days||+10||85||2%||Target must be an uncivilized country with no more than 2 states OR no more than 5 states if attacker is a great power and has researched Nationalism and Imperialism.||Annexation. Territories will become colonies.|
|Dismantle Fortifications||200 days||+4||10||10%||Target has at least one state with a fort or naval base built||Destroys all forts and any naval base in selected state.|
|Liberation||-||0||10||Varies||Attacker has core on target state. Automatic, doesn't need to be justified.||Cedes state to victor.|
|Restoration of Order||-||0||10||100||Attacker has core on all of target's provinces. Automatic, doesn't need to be justified.||Annexed by victor.|
|National Liberation||-||0||10||Varies||Target state belongs to union of attacker's culture group, and defender is from different culture group. Attacker must be a great power and have researched Nationalism and Imperialism. Automatic, doesn't need to be justified.||Cedes state to victor.|
|Assert Hegemony||-||0||10||100||Attacker and defender are both Great Powers, in the same culture group, and not unions; defender has at least one sphere member of the same culture; attacker has Nationalism and Imperialism. Automatic.||Transfers all same-culture-group sphere members to attacker.|
|Install Communist Government||200 days||+5||70||2%||Must be a Great Power and Proletarian Dictatorship. Target must not be a Great Power, not have a Communist ruling party, and have 10% Communists||Removes current government type and changes it to Proletarian Dictatorship, and adds them to victor's sphere of influence.|
|Uninstall Communist Government||-||-||5||2%||Must not have a Communist ruling party. Target must be a Proletarian Dictatorship. Must have fought against the war to install communism in target country. Expires after one year.||Removes Proletarian Dictatorship and replaces it with the victor's government type, and adds them to the victor's sphere of influence if a great power.|
|Containment||-||-||4||7.5%||Target must exceed 25 infamy.||Same as both Cut Down to Size and Humiliate.|
|Become Independent||-||-||30||10%||Attacker is a satellite of the target nation.||Loses attacker as a satellite.|
|Cut Down to Size (Boxers)||-||-||50||10%||Automatically granted to all great powers after Boxer rebels successfully hold Chinese province for one month||Same as Cut Down to Size.|
|Great War Capitulation||-||-||0||18%||Automatically added and applied to losers in wars involving multiple Great Powers on both sides once Revolution and Counterrevolution is researched||Same as Cut Down to Size.|
|Repay Debts||-||-||5||5%||Automatically granted through event to all of a country's creditors when it goes bankrupt.||Force to continue to pay interest.|
|Status Quo||-||-||1||5%||Automatically granted when intervening in a defensive war of a nation that is Friendly towards the country or in its sphere of influence.||White peace.|
Types of casus belli
There are two instances where this Casus Belli is useful to use. The maximum amount of infamy you can receive is +4.
Sometimes, Great powers can find themselves diplomatically competing for political and economical control over a smaller, independent nation. In case there is no competition, a less patient Great power can choose to bypass the tedious influence system in favor of a quicker, more militaristic approach.
Example: The United States and the United Kingdom are fighting for diplomatic control over an independent (as in not sphered) Japan. Both get discredited and banished by each other making the process long and tedious. The USA then decides to use this Casus Belli by attacking Japan and forcing it to be under USA's diplomatic control.
This Casus Belli requires the following conditions to become unlocked.
- (*) The target nation must not be a puppet.
- (*) The attacking nation must be a Great power.
- (*) The target nation must not be a Great Power.
- (*) The target nation must not be sphered by another Great Power.
Chance of discovery while justifying
Every day, there is 1.5% chance (0.015) of a war justification being discovered (this variable is stored as CB_DETECTION_CHANCE_BASE in the defines.lua). Therefore, the chance of being undiscovered at any particular day 'd' is equal to (1-0.015)^d. For example, if a casus belli takes 180 days to justify, the chance of never being discovered is (1-0.015)^180 = 0.0658 = 6.58%.
Therefore, the chance of getting some infamy n from a war justification that gives a max infamy penalty of m and takes d days to justify is equal to: 0.985^(d - (dn/m))
For example, if we are on 15 infamy and want to get 10 or less infamy to stay under the 25 infamy cap, but want to justify an acquire state cb that takes 308 days and could give us 11 infamy, the chance of us staying under the infamy limit is:
0.985^(308-((308*10)/11)) = 0.985^(28) = 0.6549595122 = 65.5%
Thus there is approximately a 2/3rds chance we'll stay under the infamy limit, and remain safe from containment wars. Such calculations are useful in calculating the riskiness of justifying a casus belli.
Being involved in a Great War will allow a player to Add Wargoal on an enemy nation that is involved in the same Great War, without requiring a percentage of the population to support Jingoism. The infamy cost is also greatly reduced to 33%
Heart of Darkness
The Heart of Darkness expansion now disables the ability to Justify War against a nation they are at war with, requiring the usage of Add Wargoal.