The outcome of Prime Minister Ishiba's visit to Washington was very encouraging because it not only exceeded expectations but also covered most of the critical issues. Here are a few takeaways:

1. The good news is that President Trump seems to understand the importance of Japan for the US in facing up to and making deals with China. Prime Minister Abe impressed this point on Trump and it has stayed in his mind. Trump was very nice to PM Ishiba, but then he is a renowned businessman who knows how to make important guests happy.

2. In dealing with the Trump administration, it makes sense to follow up with written statement. While it is impossible to cover all the points contained in the Joint Statement during the meeting, where the host tends to speak much longer than the guest, almost all the important points on which Japan wanted some reconfirmation from the Trump administration, including DPRK denuclearization,the importance of maintaining peace and stability across the Taiwan Strait and the importance of the FOIP and the lattice of cooperation encompassing Japan-US-ROK, Japan-US-Philippines and other multilateral groupings, were addressed in the Joint Statement.

3. Despite all these positive takeaways, we cannot take anything for granted considering what has happened since then. Universal application of higher tariffs and heated political debates with important allies in Europe are a perfect recipe for intensifying the fundamental concerns described below, which are exacerbated by the US president's low credibility.

My basic assessment is that the impact of the Trump administration 2.0, if present trends persist, should be considered substantial and long-lasting. What is important now is not to guess what Trump may do, which is still unclear, but work out what Japan can do and make proposals such as those described below.

1. Selective involvement in international conflicts = advent of a challenge-sharing era

The US is capable but increasingly unwilling to engage in dispute resolution. This is a problem not just for Trump but for the entire United States. Although Trump appears to be an unpredictable person, he is not actually a "military hawk".

He hates to see the blood of US soldiers spilled over issues that do not have direct relevance for the national interests of the United States and he has inherently little sympathy for alliances.

The world will thus irreversibly change from an era of burden sharing, in which the United States resolved disputes and the costs were shared among allies and like-minded countries, to an era of challenge sharing, in which allies and like-minded countries must be involved in the conflict resolution itself or otherwise disputes will continue.

The key to a ceasefire in Ukraine is to prevent a re-invasion by Russia, but the US does not seem willing at the moment to make efforts to this end, so a mechanism is needed by which NATO members in Europe, among others, send troops to Ukraine to monitor the ceasefire, with any attack by Russia triggering NATO's joint defense. Whether this can be achieved will be the first test for the challenge sharing system.

At the same time, this means that we will move from an era in which solutions were achieved through "rule by force" (fear of the US) to an era of "majority rule" in which solutions are justified by the support of most of the international community. This will make it essential to engage and gain support from the influential Global South countries.

2. "America First" principle = alliances are not a privilege

Secretary of State Marco Rubio said at a recent Senate hearing that the State Department's actions will be judged on whether they make the United States "stronger, safer, or more prosperous." Countries will no longer be given a pass "because they are allies", and the criterion for evaluating relations will be whether they contribute to the "America First" policy through concrete actions.

Countries that do not meet this criterion, whether they are allies or not, are not of interest to the Trump administration and could be abandoned. Ishiba's visit showed Japan to be fine in this regard, but I have rarely heard Trump officials talk about the US's ally the Philippines or other countries in Southeast Asia.

These countries will therefore need to be protected by neighboring Japan. One idea is to create an "Asian Quad" consisting of India, Indonesia, Japan, and Australia, and systematically draw Indonesia, which recently joined BRICS, to our side.

Considering the important role of the Philippines in the event of a Taiwan contingency, support of the Philippines will be crucial. It would also be a good idea for Japan to support the Philippines' efforts to garner cooperation among the coast guards of Southeast Asian countries and conduct joint exercises in the South China Sea. Another idea is to encourage the ASEAN Secretariat to bring the South China Sea dispute to an international arbitration tribunal again so that the issue stays on the international community's radar screen.

In any case, Japan must have the resolve and readiness to act as if "Japan were to take care of the stability in Southeast Asia." These actions listed above will make the United States stronger, safer, and more prosperous and will therefore also help strengthen the US-Japan alliance.

3. The US's "wolf warrior diplomacy" = loss of trust and friends

Trump seeks US control of Greenland and the Panama Canal and does not even rule out the use of military force to achieve this. The United States today differs from Russia in only one respect - that it has not actually used force -- and it is very unlikely to do so in this instance.

Behind this is the "exceptionalism" which holds that a major power can create a desirable order for itself. Trump himself thinks he survived assassination attempts because he was chosen by God.

The reason why the world has been basically stable since World War II is that the lessons of the two world wars have led to a consensus on such basic principles as a rules-based order, the equality of sovereign states, the maintenance of territorial integrity, and the prohibition of unilateral changes of status quo by force, as embodied in the UN Charter, and the United States has been ready to maintain this order by force.

The impact of the US not only stopping its efforts to maintain the order but also being less hesitant to destroy it could be very significant. The post-war order could fundamentally collapse, and the United States could irreversibly lose the good will and trust it has accumulated since the end of WWII.

This could have very serious repercussions for a US ally such as Japan, making it an urgent task to engage the influential countries of the Global South to manage an era of majority rule.

For example, it would be a good idea to create a group of Permanent Outreach Partners (POP) so that, whoever may hold the G7 presidency, POP will be always invited to G7 meetings. POP would include India, Brazil, Indonesia, the ASEAN chair country, South Africa, the AU chair country, Saudi Arabia, Turkey, South Korea and Australia. Perhaps Japan should start consulting with France, next year's G7 chair, about this idea before celebrating 50 years since the first G7 meeting with a new round of G7 meetings in 2026.

All in all, Japan is in a unique position, remaining an important ally of the United States without becoming a primary target of Trump 2.0 and being willing and able to support both the existing global order and the United States. This should be a time for Japan's diplomacy to flourish.