The increasingly loud debate over the future of alliances -- after reports that the US could scale back or even withdraw from Nato -- is nerve-racking. It has caused alarm across Europe and in Southeast Asia, another node of the US alliance network. Even without any official decision, remarks by US President Donald Trump on social media were enough to shake already fragile US alliances. The question now frequently asked by Thai policymakers is: What comes next if alliances weaken?
Many analysts say no single system will replace existing alliances. Instead, the world is moving toward a more flexible, multi-layered structure. One concept is the "multiplex world", coined by Amitav Acharya, Distinguished Professor of International Relations at American University. In simple terms, it is a system with multiple centres of power and rules, without a single leader.
The Nato controversy highlights a deeper challenge. After World War II, US alliances functioned largely because Washington was seen as a reliable security partner. That long-standing assumption is no longer certain. Over the past year, Mr Trump has imposed tariffs on both allies and rivals, including the EU, Canada, Japan, South Korea, and Asean. This has created unpredictability, often shifting by the day -- or even in response to a few lines on social media. His words and demeanour have unsettled global confidence.
Unsurprisingly, allies are now searching for alternatives as traditional security guarantees grow less certain.
This creates an opening for so-called middle powers. In January, they found encouragement in remarks by Canadian Prime Minister Mark Carney at the World Economic Forum. He argued that middle powers must play a more active role in shaping the global order as great-power leadership becomes less reliable. They can no longer depend on major powers to provide stability or uphold a rules-based order.
Middle powers, therefore, should work together to defend open trade, strengthen institutions, and manage global risks -- from economic shocks to security tensions. Rather than choosing sides, they should build flexible coalitions and practical partnerships based on shared interests.
This thinking aligns with Japan's push to build new trade frameworks led by middle powers. In recent years, Tokyo has promoted high-standard agreements such as the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, even without full US participation.
Meanwhile, the Asean-led Regional Comprehensive Economic Partnership has helped reinvigorate multilateralism. Recently, Japanese academics have even suggested creating an alternative framework to the World Trade Organization.
The idea of building networks of like-minded economies is gaining traction. Together, they can set standards, reduce dependence on any single major power, and keep globalisation functioning. Put bluntly, they do not want Mr Trump calling the shots and disrupting the system.
In a more fragmented world, middle powers are gradually emerging as rule-setters, shaping a new global order through complex networks. Even small states can exert influence -- Trinidad and Tobago on climate policy, or Barbados through financial initiatives at the UN.
At the same time, smaller and middle powers now have more options. Groups such as BRICS+ and the Shanghai Cooperation Organisation have expanded, while regional platforms continue to grow. This gives countries more room to manoeuvre and more partners to choose from.
In Asia, China has promoted "strategic partnerships" as an alternative to formal alliances. Beijing maintains such partnerships with more than 80 countries. These ties are broad and flexible, without the rigidity of Nato-style commitments. It has also advanced the Global Security Initiative, emphasising that no country should strengthen its own security at the expense of others.
In this environment, strategic partnerships are becoming the preferred model. They allow cooperation without rigid commitments, fitting a world where interests shift, and risks are diffuse.
The US threat to withdraw from Nato also weakens calls for an "Asian Nato". The idea is effectively dead. Asian countries differ widely in threat perceptions, political systems, religious beliefs, and historical experiences. Asean members in particular fear that such alliances would undermine regional stability and the "Asean way."
Mr Acharya argues this is not a temporary phase but a structural shift. No single country -- not even China -- will replace the global role once played by the US. Instead, regions are developing their own approaches, producing a plural, rather than unified, global order.
Asean, in fact, has long demonstrated how this model can work. As a grouping of middle powers, it engages all major players while avoiding exclusive alignment. In today's context, this approach is gaining renewed recognition.
For decades, Asean has helped build shared norms. Its 1976 Treaty of Amity and Cooperation, signed in Bali, has been adopted by around 60 countries, including all UN Security Council members.
This year in Manila, Asean will mark the treaty's 50th anniversary by urging signatories to uphold its principles in practice. A temporary moratorium on new accessions was also introduced at the 47th summit.
In an unpredictable global landscape, these norms provide common ground for both large and small powers. Asean also plays a central role in forums such as the East Asia Summit and the Asean Regional Forum, helping to sustain dialogue and reduce tensions.
For the incoming Anutin 2 government, sworn in yesterday, this shift raises a key question: Should Thailand rethink its long-standing alliance with the US? The answer is not straightforward. The alliance remains valuable, particularly in defence cooperation, training, and regional stability -- exemplified by the long-running Cobra Gold exercises.
However, Thailand cannot afford to stand still.
It needs a careful, gradual recalibration. Maintaining close ties with Washington does not preclude building new partnerships. Thailand should expand cooperation with China, India, Australia, and the EU, while deepening its role within Asean and using regional platforms to enhance its profile.
This approach fits the emerging "multiplex world." It allows Thailand to keep its options open, reduce risk, and adapt to uncertainty, while preserving strategic autonomy.
One caveat remains. Mr Acharya warns that a multiplex world is not inherently safer -- only more diverse and less dominated by a single power. That creates both opportunities and risks.
For Thailand and Asean, the challenge is clear: strengthen regional institutions, uphold shared norms such as the Treaty of Amity and Cooperation, and build links across the Global South. In doing so, they can help manage a more diffuse and complex global system, rather than one dominated by a single hegemon.
