Japan’s sharp increase in military spending and strategic realignment is not an act of aggression but a necessary measure to deter conflict, former environment minister and prominent Liberal Democratic Party figure Shinjiro Koizumi has told the BBC. In an exclusive interview, Koizumi insisted that Tokyo’s defence build-up, the largest since the Second World War, was a direct response to a deteriorating regional security environment.
“The world is not becoming safer. The war in Ukraine, Chinese assertiveness and North Korean provocations demand a clear-eyed approach,” Koizumi said. “Japan’s pacifist constitution has long been a source of pride, but it was written for a different era. Today, deterrence is the best way to preserve peace.”
Koizumi’s remarks come as the government of Prime Minister Fumio Kishida finalises a new national security strategy that commits to doubling defence spending to 2% of GDP by 2027. The plan includes acquiring long-range strike capabilities, expanding the role of the Self-Defence Forces and deepening security cooperation with the United States, Australia and other like-minded partners.
Critics, both domestic and international, have warned that such moves could escalate regional tensions and erode the post-war norm of military restraint. Koizumi, however, rejected the notion that Japan’s actions were provocative. “We are not increasing our budget to attack anyone. We are doing it to protect our people and territory. The risk of conflict comes from weakness, not strength,” he said.
He pointed to Russia’s invasion of Ukraine as a cautionary tale. “If Ukraine had been better armed, would Putin have invaded? The answer is clear. Deterrence works.”
Koizumi also addressed concerns about Japan’s reliance on US nuclear umbrella and the possibility of joining the AUKUS pact. “Japan is not considering nuclear weapons. Our commitment to the Non-Proliferation Treaty is absolute. But we must be realistic about the threats we face. The AUKUS conversation is about technology, not nuclear arms.”
On China, Koizumi struck a dual tone. “We seek a constructive relationship with Beijing. But we cannot ignore the militarisation of the South China Sea, the pressure on Taiwan and the aggressive pursuit of technology theft. Dialogue must be backed by deterrence.”
When asked about public opinion in Japan, where pacifist sentiment remains strong, Koizumi acknowledged the challenge. “The Japanese people understand the world is changing. They do not want war. They want peace. But they also want their country to be able to defend itself. This is not about abandoning our principles. It is about adapting them to reality.”
Koizumi, the son of former prime minister Junichiro Koizumi, is widely seen as a future leadership contender. His defence stance, long considered a taboo in Japanese politics, is now part of the mainstream debate. Whether this shift will lead to greater stability or trigger an arms race in East Asia remains an open question.
