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Forms of Government
From EU3 Wiki
The following types of government are possible:
Nation-specific: Celestial Empire
The following parameters describe characteristics of different government types.
- Activation: Most governments have a prerequisite Government tech for activation. Change from tribal governments and change to Empire requires both a technology and a decision. Revolutionary Republic has several triggers plus a technology. In Heir to the Throne, Merchant Republic is only accessable by decision.
- Administrative Efficiency: The cool-down period between making changes domestic policy sliders in years divided by 10. For example, an administrative efficiency of 1.20 means a wait of 12 years.
- Policy Minimum: Some governments limit the position of domestic policy sliders. Because domestic policy sliders are on a scale of -5 to 5, a minimum means sliders should not move below a certain number. While it is possible to exceed a minimum or maximum, each step beyond the limit adds a permanent +1 national revolt risk modifier until a switch to a more permissive government.
- Policy Maximum: Maximums work in the opposite direction of minimums with the same effects.
- Magistrates: New to Heir to the Throne, each government adds a certain amount of magistrates per year.
- Special: Governments offer several kinds of economic or military bonuses such as tax or trade efficiency modifiers, morale or the royal marriage ability.
- Election Cycle: A republic-only aspect which decides the length of a ruler's term. Election options allow the player to reelect the incumbent or elect a new candidate with either an administrative, diplomatic, or military emphasis. Elections are also held if a ruler dies during his term, which restarts the cycle.
Government Change Stability Cost
Conversion between different types of governments costs stability and the cost is given as a multiplier. Multiply the figure by 2 to get the actual stability cost. A change cost of .5, for example, actually means a loss of 1 stability. Governments can only convert between the ones listed in this section. For example, a Theocracy cannot become a Constitutional Republic without intermediate steps.
Government Conversion Charts
This is a list of the government types that can be switched to from this government type. The number indicates the amount of stability that will be lost in the transition. There are restrictions in the game as far as government changes are concerned. Which government types you can switch to depends on your current type. The image below shows the possible changes (thanks to Helius , Lloyien , Anti-Tank  and others). In addition to the possible changes shown below(Only way in DW), you can change from Tribal Despotism to Despotic Monarchy, Tribal Federation to Feudal Monarchy and Tribal Democracy to Noble Republic via the decision, Reform Tribal Government.
Mostly the same as in HTTT, but government change from Tribal system is possible only through Westernization from Gov. tech level 10 on. Additionaly, Divine wind introduced new unique governments: Shogunate and Celestial Empire, for Japan and China respectively. These governments can change only as described in their info pages.
There are also some changes in magistrate rates and administrative efficiency. The values in the HTTT chart are therefore not necessarily reliable for Divine Wind.