During the Gulf War (1990–1991) the Japan Self-Defense Forces couldn't participate due to restrictions of the 1947 constitution. However, Japan did make a financial contribution of $10 billion and sent military hardware. Japan's inability to send troops was regarded as a big humiliation. They learned that only making financial contributions (checkbook diplomacy) did not earn Japan international respect. Furthermore, Japan couldn't provide much support to US forces which caused frustration. This humiliation was decisive in making policymakers and military planners determined to depart from Japan's pacifist foreign policy.