A theory which states democracies do not engage in armed conflict with other democracies. The theory states that the following factors are responsible for the peace between liberal states.

1. Democratic leaders are forced to accept culpability for war losses to a voting public.

2. Publicly accountable statesmen are more inclined to establish diplomatic institutions for resolving international tensions.

3. Democracies are less inclined to view countries with adjacent policy and governing doctrine as hostile.

4. Democracies tend to possess greater public wealth than other states, and therefore eschew war to preserve infrastructure and resources.

Opponents to the theory state that democracies are too young. They believe that democracies have not had the opportunity to fight one another, while other forms of government have had centuries.