The certainty that once surrounded East Asia's security, traditionally underpinned by U.S. military power, is being eroded.
It is unclear how President Donald Trump's administration will use its military power as it implements its "America First" foreign policy, nor what it will do about the alliance relationships that are being undermined.
At the same time, China's economic growth and military modernization has made it a serious actor on the global stage.
Regional institutions -- such as the Association of Southeast Asian Nations and the East Asia Summit -- as well as international laws and a dense web of international agreements contribute to stability. Yet the current arrangements are not up to managing the two most serious challenges destabilizing the region: U.S.-China tensions and North Korea's nuclear weapons.
Political leaders also appear increasingly inclined to prioritize short-term domestic political gains at the expense of long-term regional cooperation.
For example, in the U.S., the report of FBI special prosecutor Robert Mueller on Russian interference may be delivered in the spring and Democrats will be considering impeaching the president. If pushed into a corner, Trump could pursue reckless populist-driven foreign policy as a diversion tactic.
On China, this could mean ramping up the trade war, despite the costs this would carry for the U.S. economy. On North Korea, if Trump feels he cannot portray diplomacy with North Korea as an achievement, he may prematurely return to 'maximum pressure' -- including military threats -- without seeing through the current negotiation process.
In China, the Communist Party's domestic legitimacy is intimately linked to economic growth, incentivizing it to end the trade war and contain the damage. Yet some China watchers argue that President Xi Jinping's rule is not as strong as it appears due to weakened growth and the anti-graft campaign which is unpopular with party elites. Thus there is a risk Xi will avoid giving the U.S. concessions to maintain his image domestically, despite the economic imperative to compromise.
In South Korea, President Moon Jae-in came to office with a high approval rating of over 80 percent, but his popularity has now plummeted. Moon's dilemma is that his popularity has relied on diplomatic outreach to North Korea to offset dissatisfaction over poor economic performance. Initiatives toward North-South reconciliation -- reopening the Kaesong industrial zone, the proposed Mount Kumgang resort, and the planned North-South railroad -- depend on progress in the U.S.-North Korea denuclearization negotiations and cannot currently be implemented.
In North Korea, the young Chairman Kim Jong Un needs to plan for the long-term transformation of the country and appears uninterested in a sudden denuclearization without receiving concessions, including security guarantees. Kim is on guard against a Libya-style denuclearization-today-regime-change-tomorrow scenario. If the U.S.-North Korea negotiations continue to stall, there is a risk Kim will return Pyongyang to its traditional divide-and-rule strategy and try to secure economic aid by playing the U.S. off against Russia and China -- a tactic made easier by Washington's confrontational approach to Moscow and Beijing.
So, what can Japan do to mitigate this unpredictability?
First, Tokyo must work proactively to persuade the Trump administration of the shared importance of long-term regional stability in East Asia. While an uphill battle, Japan is well-positioned to do this given the framework of the U.S.-Japan alliance, the two countries' common interests, and Prime Minister Shinzo Abe's close relationship with Trump.
Second, the trade war between the U.S. and China is a lose-lose proposition. It damages the U.S. and Chinese economies, global growth, and the rules-based international trading system which underpins shared prosperity. The root of U.S.-China tensions, as the targets of U.S. tariffs show, is the battle for supremacy in high-tech industries between China's state-led communist system and the U.S.'s market-led capitalist system. Frustrations with China's methods of acquiring technology -- lax intellectual property rights, investment laws which require joint ventures and forced technology transfer, and generous state subsidies funneled to favored companies -- means a quick agreement to resolve the U.S.-China tensions is unrealistic.
A new consultative mechanism between the U.S. and China is needed to address these issues. These consultations must emphasize WTO commitments and should be linked to the G-20's WTO reform agenda as Japan prepares to host the Osaka G-20 Summit in June 2019. Tokyo can clearly lend a helping hand.
Third, Japan and South Korea must fix their deteriorating relations. Failure to resolve tensions undermines security cooperation between the U.S., Japan and South Korea, and efforts to create a united front in negotiations with North Korea. Japan-ROK quarrels resurfaced in October 2018 when the Seoul Supreme Court order Nippon Steel to compensate plaintiffs for work as forced laborers during World War II. This legal wrangling risks undermining the foundation of Japan-ROK relations set out in the 1965 Japan-South Korea Basic Treaty under which Japan and South Korea normalized relations and all wartime claims were settled.
Seoul must reconcile the gap between its domestic law and its international agreements. Meanwhile, both governments should refrain from provocative statements which complicate reaching a diplomatic solution.
Fourth, Japan and China should continue to expand cooperation to promote free trade and the rules-based order. Relations have improved recently with Prime Minister Abe's visit to Beijing in October 2018 and the agreement for joint cooperation on 52 infrastructure projects in third countries to deepen regional infrastructure links.
Further cooperation between the two nations should include working on the early conclusion of the Regional Comprehensive Economic Partnership, the proposed Asian trade pact. Such strong collaboration between Japan and China on trade may be the right message to the U.S. to persuade it to reconsider its protectionist approach.
Fifth, working-level consultations between the U.S. and North Korea are absolutely crucial. The top priority before a second Trump-Kim summit meeting must be establishing a road map implementing denuclearization in exchange for economic assistance and security guarantees. A second summit must be more than just a show. The lack of a sustainable road map ultimately saw past North Korea agreements fail, such as the 1994 Agreed Framework and the September 2005 Six-Party Talks joint statement. This time, a road map must include step-for-step sequencing and a multilateral supervisory body to verify compliance.
Now is the time for national leaders to put short-term political gains aside and work together to put the region back on a path to stability rooted in peace and prosperity. Japan must play a central role.
Hitoshi Tanaka, former deputy minister for foreign affairs and a key adviser to then-Prime Minister Junichiro Koizumi, is chairman of the Institute for International Strategy at Japan Research Institute.