A Mechanism for Democratic Peace Theory

Long-time Dean’s World readers are no doubt familiar with the Democratic Peace Theory — the observation that liberal democracies don’t seem to make war on other liberal democracies. I’ve been thinking about why, and in addition to the standard explanations (see the Wikipedia article), I’ve come up with another idea.

Non-democratic states may aspire to conquer other states regardless of the institutions of the targets of their aspirations. If you have an authoritarian regime at home, extending it to conquered territories is a relatively straightforward matter.

Democracies may aspire to liberate authoritarian states. Rightly or wrongly, they can reasonably come to the conclused that if they destroy the authoritarian regime and install democratic institutions, the currently-authoritarian state would be transformed to the benefit of both countries.

Democracies cannot reasonably aspire to conquer or liberate other democracies. Suppose modern Britain and France went to war with each other for some reason. Suppose France wins completely, destroying the Royal Navy in a single battle and successfully launcing the first successful cross-channel invasion since 1688. Now what? Is France going to annex Britain and allow 60 million Britons to vote in French elections? Or is France going to withdraw and leave Britain independant after overseeing elections which will likely choose politicians who support precisely the same policies France went to war to stop in the first place?

Since a democracy’s benefit from utterly defeating another democracy is fundamentally limited, conflicts between democracies tend not to escalate. Either they’re resolved in a purely diplomatic fashion, or the military gets involved in bloodless posturing. The Pig War of 1859 is another excellent example of two democracies resolving a potentially violent conflict peacefully because neither has any hope or desire to conquer the other.

There is a third possibility — France could reestablish a dual system of democracy at home and authoritarianism in the Empire and integrate conquered Britain as an imperial possession. This has gone out of fashion lately as we’ve decided that human rights don’t end at the water’s edge, but it used to be common practice. But from the standpoint of studies verifying Democratic Peace Theory, states which have large imperial possessions which they rule in an authoritarian manner are not considered liberal democracies because a large number of people subject to their juristiction have no say in government.

Without imperial possessions as an option, the only possible aspiration for a major war between democracies would be the annexation of a sparsely populated resource-rich hinterland suitable for colonization. It could happen — Mexico was not a democracy in 1848 when the US-Mexican war started, but the United States could and did conquer and annex what’s now the American southwest with the aim of opening it to American settlement. The American goal was to acquire the largest part of Mexico while acquiring the least number of Mexicans (I think this is a direct quote from a US politican at the time, but I can’t find a citation). In the 20th century, however, where the overwhelming majority of liberal democracies which have ever existed exist, there are not many sparsely-populated resource-rich hinterlands left to fight over.

To sum up, Democracies do not make war on Democracies because their institutions prevent them from having any points of contention worth fighting a major war over.