Defense Uncertainty:
The United States No Longer Gives Unconditionally

"The core purpose of Japan's defense buildup is to induce a greater level of American commitment." — Ken Jimbo
By ｜ Kolas Yotaka

Kolas Yotaka is a Taiwanese author and politician. She previously served as spokesperson for both the Executive Yuan and the Office of the President. A former legislator with the Democratic Progressive Party, she now leads policy initiatives focused on supply chains, defense, and energy security.

A Taiwan Contingency Is a Japan Contingency? A Beautiful Misunderstanding
 
Japanese Prime Minister Takaichi Sanae has swept the world like a whirlwind, and Taiwan has caught that wind too. Most Taiwanese would place Takaichi firmly at the pro-Taiwan end of the political spectrum. When she cited Taiwan as an example in Diet proceedings in November 2025, using it to define the conditions for a "survival-threatening situation" under Japanese law, as a framework for determining whether Japan would deploy forces, the CCP responded with animal-like fury, launching irrational economic and military sanctions against Japan and personal attacks against Takaichi herself. The more the CCP lost control, the more votes Takaichi won. The more the CCP lost control, the more excited pro-Taiwan voices became, projecting the CCP's rage at Takaichi as a direct measure of how "pro-Taiwan" she actually is.
 
The source of Takaichi's statement about a Taiwan contingency was not a carefully prepared diplomatic position. According to Ken Jimbo, it was closer to an accident.
 
I did not think that there was any strategic motivation to provoke this issue, from Prime Minister Takaichi, her office, the foreign ministry, the ruling party, or anyone else.It was an accident, in the sense that there was no intention on her part to provoke such a harsh Chinese response. There's a lot of evidence for this. She didn't read from any text when she made that statement. It came about only in response to repeated questions from the opposition, which kept pressing her until she finally said it. And her statements after the incident returned to normal. Japan remains committed to its basic agreements with China.
 
But if it was unintentional, why won't Takaichi take it back? Jimbo explains that this is where the situation becomes genuinely complicated.
 
China may wonder why Takaichi is not willing to retract the statement she made on November 7th. But there's another tricky issue involved. What Takaichi mentioned is quite normal to us. Of course we are preparing for that scenario, but we didn't say it out loud. That's the basic nature of these things. But she said it, and she cannot retract it, because that's what we are actually preparing for. We respect China enough that we don't openly say we will go to fight with them over Taiwan. That's not peacetime diplomatic behavior. But during a crisis or in wartime, this is exactly what Japan is entitled to do under the new security legislation and alliance dynamics. So China requesting us to retract a statement about our own preparedness is absurd to us. You simply cannot do it. And if we retract it, that's effectively the end of the alliance. We would be officially saying that if the United States intervenes in Taiwan, we will not offer any support. That's not going to happen. China's request, to me, is simply absurd.
 
 
Binding with America: The Best Card Is Increasing the Defense Budget
 
Japan's defense is bound to America's, there is no other option. The United States is the ultimate backstop of Japan's defense, the foundation on which it rests. In 1960, Japan and the United States signed the Treaty of Mutual Cooperation and Security in Washington, establishing the framework of the Japan-U.S. alliance to counter the expansion of China, North Korea, and Russia in the Western Pacific. The core provision, Article 5, stipulates that when Japanese territory comes under armed attack, the United States will intervene and both countries will act together to repel the threat. This is why the United States maintains military bases and stations troops in Japan. If the United States takes any military action in the Western Pacific, Japan is also obligated to commit forces. However, since Trump's return to power, the substance of the Japan-U.S. security arrangement has undergone a qualitative change. A new game has emerged. America's long-standing security commitments to Japan and Northeast Asia have become transactional.
 
Since Trump's return to power, the United States has become, I think, much more conditional. In a way, the United States no longer identifies itself as a guarantor of peace in this region without conditions. Japan needs to earn the credibility of the United States commitment here much more than under previous administrations. The uncertainty rises on one side from the security situation, which is becoming very severe. But at the same time, Japan's architecture for creating deterrence needs to be built by ourselves. This is the major uncertainty that Japan now faces.
 
In Jimbo's view, faced with this transactional turn in the Japan-U.S. security relationship, the Takaichi government needs bargaining chips. The best card it holds is increasing Japan's defense budget, strengthening the development of Japan's defense industry, and building up its own self-defense capabilities. Only by making Japan's indispensability to American strategic interests unmistakably clear can Japan keep the United States at the table, and the two countries can play their hand together effectively.
 
We are committed to increasing our defense budget and capabilities dramatically, in order to earn the capability and resolve to deal with the potential scenarios we face, especially in the gray zone and in low- to medium-intensity conflict, by ourselves. But that doesn't mean Japan is aiming for strategic autonomy, or a Plan B that positions itself away from the United States. That is not the case. After all, we definitely need escalation control capability that includes the United States, and that will guarantee Japan's strength in dealing with the risks and threats I mentioned. How much Japan can draw on United States credibility and commitment is essentially the most important question behind our capability increase. Our intention is of course to increase our own capability, but that capability will also serve as an important backstop for inducing the United States to commit.
 
Facing China, Japan needs to keep the United States firmly bound to it, for the sake of Japan's own security and strategic advantage. In Jimbo's view, China poses a threat to both Japan and Taiwan, but the nature of those threats is fundamentally different. In terms of territorial claims, Japan and China have only the overlapping sovereignty dispute over the Senkaku Islands (Diaoyu Islands), whereas Taiwan faces China's claim that Taiwan is part of China entirely, with the CCP refusing to renounce the use of force to bring that about. The pressure on Taiwan is far greater. Jimbo makes clear that he does not believe the CCP currently harbors any ambition to seize Kyushu or Okinawa. Under the spirit of the Japan-U.S. security treaty, unless China attacks Okinawa or Kyushu, or the United States commits forces to a Taiwan Strait conflict, Japan will not deploy troops for Taiwan's sake alone, however much sympathy it may have for Taiwan.
 
I do not think that Japan can act as an individual actor to intervene in a crisis without a firm United States decision to intervene. This means that exposing ourselves to a Taiwan Strait contingency through our own capability alone has certain limits. Even though we have some long-range strike capabilities, and our air force can operate near those waters, that doesn't mean we are ready to fight the Chinese PLA solely by ourselves in a Taiwan contingency. That should be kept separate from other types of scenarios, like a blockade, gray zone coercion, or information warfare, where Japan would certainly respond. But if China indicated it would counter-strike on Okinawa or Kyushu, and people would be killed, are we determined to enter that scenario without a United States decision to intervene? That is quite doubtful. That's my own take.
 
Should a Taiwan Strait conflict occur, Jimbo believes that demonstrating the will to resist and oppose aggression is critical. The Japan-U.S. alliance is itself an expression of that will, and a deterrent to the CCP.
 
In terms of U.S. military presence, mobility, and exercises, things remain quite robust. We have constant joint exercises that signal to Chinese leaders that we are ready to intervene whenever China tries to take that course of action. That remains intact. Japan is upgrading its level of interoperability with the United States, and we are ready to collaborate whenever the United States is ready to act.
 
Japan's most careful and deliberate statement on Taiwan Strait security is therefore to raise its defense budget, a form of strategic ambiguity that is expressed through action, not words.
 
Japanese policy is signaling to China that we are firmly committed to the alliance, and our alliance partner, the United States, is also conducting its own strategic ambiguity toward Taiwan. That is the basic structure of Japan's policy.
 
 
But Will the CCP Actually Attack Taiwan?
 
I would say conditionally that if the opportunity appears wide open for China, meaning that the United States will not intervene and there is a clear pathway to a successful military operation, China will certainly be tempted to move in the military domain and seek that opportunity.
 
The way to deter the CCP, then, is to build up defense capabilities.
 
They are inclined to do it. So how much we can close the window of opportunity for China is essentially the most important thing we are doing. By conducting exercises, deploying capabilities, and sending the signal that this is not going to happen, and that if they try, the damage China will have to accept will be enormous. These are the messages we are constantly sending. If we are successful in maintaining this stance, a Taiwan contingency will not happen. But if we are not doing enough, it could. This is the dynamic I wish to lay out.
 
Jimbo also offers a counterintuitive observation: a weak Taiwanese government, in his view, actually reduces the likelihood of a CCP attack.
 
The current DPP does not have a majority in parliament, and Taiwan is going through local elections soon, with a presidential election in a few years. There is still uncertainty about what the results will be. That leaves the CCP with the hope that a pro-China political configuration could emerge. And interestingly, that fragility in Taiwan's politics gives China and President Xi Jinping a full excuse not to intervene militarily, because they still believe peaceful political change is possible. So while Taiwanese may not be entirely comfortable with that political fragility, it is precisely that fragility that gives the CCP a reason to hold back. It's a very interesting dynamic.
 
No government, of course, would want to be that weak.
 
Personally, what I wish for President Lai is to stay resilient on Taiwan's posture, both militarily and in terms of the security authorities and the people, so that any kind of Chinese pressure does not undermine Taiwan's confidence and resolve to determine its own future. That is something that many in the world fully support. At the same time, we would not want Taiwan's leader to openly become a belligerent state toward China, expecting that Japan and the United States will back Taiwan under any circumstances. Of course, we are prepared to support Taiwan even if it takes a more proactive stance in pushing back against Chinese pressure. But whether we are better off fully supporting that stance, in whatever context of tension may arise from such a proactive position taken by President Lai Ching-te, is a very nuanced question.
 
Jimbo adds that if the CCP were to use force, the Japan-U.S. alliance would of course be entitled to intervene. But maintaining strategic ambiguity, doing without saying, is the ABC of what Taiwan's politicians should understand when seeking American and Japanese defense commitments. This, he notes, is quite different from what most Taiwanese people expect.
 
Taiwan's projection onto Takaichi Sanae may have gone too far. Building up its own defense capabilities is the only path that truly matters.
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