Japan has signalled its intent to join the United States' ambitious "Golden Dome" missile defence initiative, with Prime Minister Sanae Takaichi set to confirm this during a leaders' summit in Washington D.C. on 19 March.

Two government sources, speaking anonymously due to the matter's sensitivity, revealed that Tokyo will formally notify Washington next week.

The announcement comes amid heightened global tensions, including the ongoing U.S.-Israeli air war against Iran and Russia's invasion of Ukraine. Japan anticipates that President Donald Trump may request assistance in missile production to replenish depleted U.S. stockpiles.

Trump unveiled the Golden Dome project last year, targeting a 2028 completion date. It aims to enhance existing ground-based interceptors with experimental space-based sensors capable of detecting, tracking, and potentially neutralising threats from orbit.

Progress on the project has been limited so far, with few concrete developments visible. Details of Japan's precise role remain unclear, though Tokyo views it as a bulwark against hypersonic glide vehicles under development by China and Russia, according to the Yomiuri newspaper's initial reporting.

The Yomiuri first broke the story on Friday, highlighting Japan's strategic motivations. Hypersonic weapons, which travel at speeds exceeding Mach 5 and manoeuvre unpredictably, pose significant challenges to traditional missile defences.

Japan's participation aligns with its recent policy shifts. Late last year, it exported a batch of licence-built Patriot surface-to-air missiles to the U.S., marking a historic departure from its long-standing prohibition on lethal weapons exports.

This move reflects Tokyo's evolving security posture. Facing an assertive China and nuclear-armed North Korea, Japan is bolstering its own munitions reserves while deepening alliance ties with the U.S.

The Trump administration has urged defence contractors to ramp up production of missiles and munitions strained by recent conflicts. U.S. stocks have dwindled due to support for Ukraine and operations in the Middle East.

Patriot interceptors have proven vital in these theatres. They have downed hundreds of Iranian ballistic missiles and drones targeting Gulf states since the U.S.-Israeli campaign against Iran began earlier this month.

In Ukraine, Patriots have safeguarded energy infrastructure and military assets since Russia's 2022 invasion. Demand for these systems has surged, prompting calls for allies like Japan to contribute.

Japan is weighing its response to any U.S. request for missile co-development or production. Sources indicate Tokyo is still deliberating, balancing domestic capabilities with strategic imperatives.

Mitsubishi Heavy Industries, a key player in Japan's defence sector, already produces Patriot missiles under licence. This positions Japan well to scale up output if needed.

The Golden Dome's space-based elements represent a technological leap. Unlike ground systems, orbital sensors could provide persistent global coverage, revolutionising threat detection.

Challenges abound, however. Space-based interceptors demand breakthroughs in miniaturisation, propulsion, and cost-effectiveness. Critics question the 2028 timeline as overly optimistic.

Japan's involvement could irk Beijing and Moscow. Both nations have criticised U.S. missile defences as destabilising, potentially spurring an arms race.

For India, a Quad partner of Japan, this development carries implications. Shared concerns over Chinese hypersonics could foster trilateral defence cooperation, though New Delhi prioritises indigenous systems like BrahMos and Agni.

Japan's export policy relaxation dovetails with its 2022 national security strategy, which pledges to acquire counterstrike capabilities. This includes long-range missiles to deter aggression.

The U.S.-Iran conflict has accelerated munitions depletion. Israel's strikes on Iranian facilities, backed by American logistics, have consumed vast interceptor stocks.

Ukraine's reliance on Western aid underscores the strain. Patriot batteries there have intercepted Kinzhal hypersonics, but resupply lags behind attrition rates.

Trump's push for allied production shares echoes "friendshoring" in semiconductors. By leveraging Japan's manufacturing prowess, the U.S. aims to diversify supply chains away from vulnerable nodes.

Economic factors play a role. Japan's defence budget, doubled to 2% of GDP by 2027, funds these ambitions. Participation in Golden Dome could yield technology transfers and joint R&D. Yet risks persist. Exporting lethal weapons invites scrutiny from pacifist constituencies and regional neighbours. South Korea, another U.S. ally, watches closely amid its own missile advancements.

The 19 March summit will clarify commitments. Takaichi, a hawkish figure, seeks to cement Japan's indispensable role in Indo-Pacific security.

Japan's Golden Dome entry signals a proactive stance in an era of multiplying threats. It underscores the U.S.-Japan alliance's resilience amid global flux.

Reuters