As the first Gulf War raged in February 1991, Ground Self-Defense Force Maj. Nozomu Yoshitomi was supposed to be conducting war games with U.S. officers at a military facility in Tokyo. But the Americans appeared distracted, watching the conflict live on CNN. On another TV, local news showed Japanese troops sculpting ice figures at a snow festival.

"They asked how Japan could be a true U.S. ally if it hadn't sent troops," said Yoshitomi, recalling the shame he felt watching Japanese personnel build snowmen as U.S.-led coalition soldiers fought to evict the Iraqi Army from the Kuwaiti desert.

Unable to send troops because of the war-renouncing Constitution, Japan, which at the time bought 90 percent of its oil from the Middle East, instead contributed $13 billion to help fund the military operation.