日本的國防姿態長期依賴一種矛盾：在強烈反對核武器的同時，卻又安全地處於美國的核保護傘之下。日本防衛大臣小泉進次郎最近因建議日本應「無禁忌地討論所有政策」而引發爭議，這番言論隨即遭到擁核鄰國以及國內反核團體的強烈批評。

小泉的目的未必是讓日本獲取核武（這在政治上過於敏感），而是希望開啟對1967年「非核三原則」的討論，特別是關於禁止將核武器引入日本領土的規定。現實情況是，日本極度依賴美國的延伸嚇阻能力，維持這些戰後的禁忌，使得日本越來越難以解釋為何在依賴核武保護的同時，卻連討論核武存在的可能性都加以拒絕。

在中國、俄羅斯和北韓不斷擴充核武庫的快速變化安全環境中，日本需要重新審視其自我設限的政策。首相高市早苗等人也曾暗示討論「核共享」的可能性；歸根結底，日本必須透過公開討論來決定其政策，而不是讓對外部反應的恐懼來界定甚麼才可以被討論。

Japan's defense posture has long relied on a contradiction: strongly opposing nuclear weapons while safely sitting under the US nuclear umbrella. Defense Minister Shinjiro Koizumi recently sparked controversy by suggesting that Japan should "discuss all policies without any taboos," a remark that quickly drew harsh criticism from nuclear-armed neighbors and domestic anti-nuclear groups.

Koizumi's objective is not necessarily for Japan to acquire nuclear weapons, which remains too politically sensitive, but to open a debate on the 1967 "three non-nuclear principles," specifically the rule against permitting the introduction of nuclear weapons into its territory. The reality is that Japan deeply depends on US extended deterrence, and maintaining these postwar taboos makes it increasingly difficult to explain why the country relies on nuclear protection while refusing to even discuss the possibility of their presence.

In a rapidly changing security environment where China, Russia, and North Korea are expanding their nuclear arsenals, Japan needs to reexamine its self-imposed limitations. Prime Minister Sanae Takaichi and others have also hinted at the possibility of debating nuclear sharing; ultimately, Japan must determine its policies through open discussion rather than allowing the fear of external reactions to dictate the boundaries of its debate.