Japan Is Back But Not The Version Washington Wants

In many ways, it was a familiar playbook – what critics have long called“checkbook diplomacy.”

Takaichi struck a careful tone. Asked post-summit whether Japan would send naval assets, she replied:“We agreed that ensuring the security of the Strait of Hormuz is indeed of the utmost importance. However, there are limits to what we can and cannot do under Japanese law, so I provided a detailed and thorough explanation of this point.”

Those limits are real and binding. Any deployment of the Self-Defense Forces would fall under Japan's 2015 security legislation. A“survival-threatening situation” would permit the use of force under limited collective self-defense. An“important influence situation” would allow rear-end logistical support to the American forces. Both require Diet approval and would face significant domestic scrutiny, particularly given public skepticism toward US military action in Iran.

Even the legal threshold is contested. During Diet deliberations in 2015, then-Prime Minister Shinzo Abe pointed to the hypothetical mining of the Strait of Hormuz as an example of a situation that could threaten Japan's survival. But Japan's substantial oil reserves – often estimated at over 200 days – have led some lawmakers to argue that even a serious disruption may not rise to that level.

There is, of course, a third option. Do what Abe did in 2020 and dispatch vessels for intelligence gathering under a low-risk legal framework. But such a move would be largely symbolic.

Looking back, this tension is not new. In 2003, the George W. Bush administration faced similar reluctance from allies as it assembled a coalition for the Iraq War. But Japan, under Prime Minister Junichiro Koizumi, ultimately dispatched around 600 Self-Defense Force personnel to non-combat areas under a special measures law, despite legal constraints and public opposition. Neighboring South Korea sent even more, at one point deploying roughly 3,600 troops.

What made that possible was not enthusiasm for the war. It was confidence in the alliance. Even as publics in both countries viewed the Iraq invasion with high skepticism, there remained a broad understanding: when the United States calls, allies respond. The alliance itself was seen as worth sustaining, even at political cost.

That assumption no longer holds as firmly.

What has changed is not just the nature of the conflict in the Middle East – it is the nature of American leadership. Trump has not simply questioned alliances; he has redefined them as transactions. In doing so, he has weakened the very logic that once made allies willing to incur political and military costs on Washington's behalf.

Even as Japan has complied with Trump's unilateral demands, from trade negotiations to increased investment in the US, it has done so in an environment where the alliance feels less like a shared strategic project than one shaped by coercive leverage.