Historical memory and institutional legacies shape political behavior over the long term. However, in some cases, traumatic memory appears to have limited influence on politics, prompting the need to understand what factors play a decisive role under what conditions. In Japan, heavily bombed areas like Hiroshima and Eastern Tokyo preserved their wartime memories through civic education and oral histories, yet exhibited pro-American conservative voting patterns, contrasting with spared regions such as Kyoto and Sapporo.

To explore this, I digitized all plants listed in the 1942 army and navy procurement records and constructed an instrumental variable based on routes between major bombing targets and U.S. air bases in Saipan or Iwo Jima. Areas on these routes were more likely to be bombed, even without military industry, as American bombers often dropped residual bombs on secondary targets on the returning journey.

My IV analysis reveals that bombed areas showed increased support for purged conservative candidates in the 1952 election, establishing a legacy that persisted into modern elections. This conservative bias, absent in 1942, appears linked to wartime bombing. The pattern was especially pronounced in regions with low-casualty local infantry regiments, whereas spared cities with high-casualty regiments tended to adopt progressive tendencies.

Through case studies, I argue that in bombed areas where demobilized soldiers led postwar reconstruction, conservative institutions established during this critical juncture diminished the impact of traumatic memories on political behavior. The leadership—whether by soldiers or civilians—during institution-building may shape the extent to which war memories influence politics, if at all.