Democratic peace versus contractualism.

If contractualism causes both democracy and peace, the correlation between democracy and peace is spurious. But the definition of contractualism is sufficiently unclear as to create doubts that it has such an impact. In addition, if democracy has an impact on contractualism, then, even with an otherwise perfectly specified model, controlling for contractualism will bias estimates of the effect of democracy on peace. International trade involves contracting behavior between strangers in different states. In addition, unlike contracting behavior within states, trade involves interactions in the same arena where interstate conflict needs to be deterred. Contractualist states have existed in significant numbers only recently. This limits contractualism’s ability to compete with democracy as a predictor of peace. Mousseau’s previous findings have been extraordinarily fragile. Finally, observational data should be complemented by multiple streams of evidence. Some experimental data support democratic peace theory; analogous experiments would almost certainly not provide evidence to support contractualism. [ABSTRACT FROM AUTHOR]