War Tension is a mechanic totally not from another game. It can encompass spheres of influence or whole nations. It goes from 0%-100%. Unrest from one or several countries in a local neighborhood contribute to the local War Tension, while tension in great and regional powers contribute to their respective spheres of influence. War tension encompassing the whole world can create a world war.
0-40%, period of little-to-no tension Edit
The most common period. The extra features from the "war tension" mechanic are disabled. Most of the world is currently in this period.
41-85%, period of tension Edit
A period of tension is where countries can wage war against their enemies indirectly. They can use indirect weapons, such as the riotmaker and gangs, to ravage their enemies. They can also spy on them without diplomatic penalties. Corporate revolution countries benefit the most from this period.
86-100%, period of war Edit
This is the period where countries are automatically at war with their enemies and vice versa, with the war initiator being mostly unclear. However, if you declare war (without the help of war tension), your tension will be raised to 90-100%, but the extra effects will otherwise be disabled for your other enemies.