Is there an aid-for-participation deal? US economic and military aid policy to coalition forces (non)participants

There is an empirical evidence of an aid-for-policy deal between the United States and other states; the United States has utilized aid programs to promote affirmative votes in the UN General Assembly and to maintain an alliance relationship with strategically important states. However, whether there is a systematic evidence of an aid-for-participation deal remains inconclusive. Does the United States generally utilize its foreign aid to reward the contribution of troops to the US-led multinational forces and to punish the lack of contribution? The author argues that US foreign aid is used to prevent free-riding in coalition participation. To test the argument, I examined whether states were punished or rewarded by the United States for their behavior in sending or failing to send troops to 15 post-Second World War US-led coalition forces. The results show that the United States punished states for unexpected nonparticipation, but did not always provide rewards for support.