During his reign from 1851 to 1868, King Mongkut or King Rama IV issued a clear directive to Siamese diplomats in the era of Western Imperialism that they must protect national sovereignty with intelligence and diplomacy.
In doing so, the late monarch said Siam must accept the diplomatic approach comes with a cost. This pro-diplomacy has safeguarded the country's sovereignty to this day.
King Mongkut's directive has become diplomatic tradition adopted by generations of diplomats at Saranrom Palace, known as the first home of the Ministry of Foreign Affairs.
Although 150 years have passed, global politics largely remain the same. Powerful nations that King Rama IV once described as "whales" and "crocodiles" continue to fight for power and exert control over smaller ones just they did during the colonial era.
In modern times with the arrival of AI, these super powers are aggressive as they once were, if not even more. The geopolitical climate follows historical patterns -- stronger nations exert power, demonise adversaries, and seize opportunities where they can. Thailand is no stranger to these dynamics.
A case in point is US President Donald Trump who is trying to make America great again through hyper tariffs and other coercive measures.
Thailand's biggest foreign policy challenges usually come from within. A common mantra dictates that all foreign policy is local and primarily driven by the country's economic interests. A country's diplomatic goal has always been the protection of national sovereignty. This goal has remained unchanged regardless of who runs things -- a junta or civilian government.
For centuries, Thailand has survived on a razor's edge thanks to the country's diplomacy. Adaptability and resilience have long been hallmarks of Thai diplomacy -- so much so that it is often called the "bamboo policy", bending with the wind.
However, seasoned Thai diplomats argue that real Thai "bamboo" knows where and how it will bend in advance. Veteran Thai diplomat Tej Bunnag once said the country's self-preservation through conciliation has been the key to survival.
Yet past achievements may not be enough to secure the future.
The conciliatory tone of Thai diplomacy is changing. Since the Paetongtarn government took office, our diplomacy has become more transactional. This exchange-based diplomacy is believed to reflect the influence of former prime minister Thaksin Shinawatra.
Over the past six months, Government House has dictated Thailand's diplomatic course, often bypassing the Foreign Ministry's top officials. Thaksin's decisions override all levels of diplomatic hierarchy and sensitivities.
Such intervention is worrying. Without a consistent and long-term strategy, Thailand will lose the ability to shape its own future.
Mr Trump's tariff hike and Thailand's reaction could serve as a good case study. It shows the government's overall response was sluggish and ad-hoc in comparison with other members of the Association of Southeast Asian Nations (Asean).
Some might hope it has the cards to deal with the US. But Thailand has yet to show its strategic planning, economic priorities, and resilience in relation to the US.
Prime Minister Paetongtarn's reliance on her father's personal networks may provide short-term advantages but it will cause a backlash.
Today's global challenges -- climate change, cybersecurity, transnational crime, sustainability, and the green economy -- require good systems and government-to-government engagement. Bold, personal decisions can be disastrous.
It is peculiar to touch on the issue of Thaksin's influence on the eve of the 150th anniversary of the Ministry of Foreign Affairs. But it is necessary as the impacts of Thailand's diplomatic shift are profound and could be serious.
Without a strong institution, policy decisions can be determined by individual preference and therefore lack coherence and consistency.
Thailand's past diplomatic finesse was built on balancing great powers while maintaining autonomy. Such diplomatic stratagems could become a thing of the past if decisions are made by a personalised and incoherent decision-making process.
Another challenge is regional diplomacy that is far more complex than the past.
Thailand must position its strategy to align with Asean while engaging with major dialogue partners, China, Japan, India, Australia, South Korea and other key players.
The Indo-Pacific region, which includes the Bay of Bengal, is increasingly contested. In future, maritime disputes, trade wars, tensions and security concerns will be factors that shape Thailand's diplomatic trajectory and define its place in the broader geopolitical landscape.
If Thai diplomacy remains personalised and, rather than standing up for its beliefs, has its principled foreign policy compromised, Thailand will eventually see opportunities for economic growth and regional leadership squandered.
Under the Paetongtarn government, more questions have been asked on the direction of Thai diplomacy.
Instead of relying on individual influence, the country must strengthen institutions and the new generation of diplomats who understand Thai diplomatic roots and long-term foreign policy objectives.
On the eve of its 150th anniversary on April 14, Thailand's diplomatic community -- both past and present -- must reflect on the nation's diplomatic history and polish up good practices that helped our country maintain its independence.
The country needs to be nimbler. By integrating traditional wisdom with forward-looking policies, it can develop public-backed strategies that reinforce our sovereignty and help us walk into future. Without public support and solidarity, Thailand's future remains in the hands of dubious leaders.
Kavi Chongkittavorn is a veteran journalist on regional affairs.
