Liberal peace thesis has its roots to "Perpetual Peace" developed by Immanuel Kant in 1700s. This theory tries to analyze the relationship of war with the political form adopted by that state. The major arguments of this theory is:
Democracies do not go to war.
"The constitution of any state should be republican." This notion is the starting point of supporting argument in order to restore long term peace. By these statements, this theory accepts democratic governance to be the only way which can build peace for a long time and any other forms of political system (i.e. autocracy, fascism, monarchy, communism etc.) are directly rejected to be eligible forms for peace. Democracy, ideological commitment to basic human rights and transnational interdependence are considered to be the three pillars of democratic peace thesis.
Explanation:
In democratic governance, the power of decision if the state is going to war or not lies upon the people. The politicians need to draw a strong support in favor of war from its citizens before commencing a war. On the other hand, people do not want to go to war because it is an additional burden to them in terms of security, economy and other calamities that are brought up to them by any war. The fear of war in people's mind helps them to decide to go against war. Without the popular support the leaders of the democratic countries cannot solely decide to go to the war because they are accountable to their citizens. Therefore, democratic states are reluctant to go to war and they try to solve any disputes in a peaceful way.
In contrast, if the country has other political forms such as autocracy, fascism, monarchy, etc. the power of decision to sanction a war lies in a single leader or a bunch of people in power. The war needs not to be sanctioned from the people that's why personal ego of the leader can sometimes be the sole reason for the state to plunge in war.
The normative explanation of this theory tends to reject the Hobbesian idea of realism in the international politics. The relations between the democracies are better than the relation between other forms of political institutions. It is because democracies share similar values, structures and agendas. This makes them to cooperate with each other for prosperity and solve the disputes using peaceful and diplomatic means.
Criticisms:
According to the different scholars, the notion of democracies not going to war is highly flawed. The first and foremost criticism involves the definition of democracy. The liberal peace thesis do not have an operational definition of what democracy means and what are the measures to evaluate either a country is democratic or not.
United States being the first democracy of the world has been involved in several wars around the globe. This empirical fact rejects the assumptions of the theory that democracies need popular support to go to war because the Iraq war was highly objected by the Americans. The counter argument scholars made was democracies do not go to war with other democracies but it can go to war with other forms of political forms. However, there are examples from the history where one democracy has invaded another democracy. In 1953, America was involved in overthrowing the elected government of Iran. UK bombarded Finland in the second world war. The war of Kargil is another example and there are other numerous events in the history where democracies have fought with each other.
Another criticism is about the intra-state war inside the democratic states. A number of civil wars have been reported after the 1990s in the countries which already adopted democratic forms of governance. Civil war started in Nepal after the country became democratic, during the Tamil war, Srilanka was democratic, Ireland is a democracy with civil war going on.
More about democratic peace thesis:
Democratic Peace Theory
Three Pillars of liberal peace
More about democratic peace thesis:
Democratic Peace Theory
Three Pillars of liberal peace
