Democracy, political similarity, and international alliances, 1816-1992

The connection between domestic politics and international cooperation, spe cifically the relationship between regime type and alliance behavior is exa mined to test two central hypotheses: democracies are more likely to ally w ith each other, and states of any similar regime type are more likely to al ly with each other. These hypotheses emerge from three theories: constructi vism, economic interdependence, and credible commitments. The authors use a data set of all pairs of states from 1816 to 1992. Results show that state s with similar regime type Ne more likely to ally with each other after 194 5, although two democracies are not more likely to ally than two autocracie s during this period, and distance, learning, threat, and common culture af fect alliance behavior, but trade does not. Results indicate sharp limits t o the connection between democracy and international cooperation.