
With the United States and Thailand kicking off the 2017 iteration of the annual Cobra Gold military exercises – Asia’s largest military drill – we have seen the usual stream of commentaries on the state of the bilateral alliance (See: “Trump and the US-Thailand Alliance”). With this, we’ve seen references to Thailand as the United States’ “oldest Asian ally.”

The matter-of-fact use of that term by some is interesting in and of itself. In commentary on U.S. treaty alliances in the Asia-Pacific, it’s common to find that both Thailand and the Philippines are referred to variously as the United States’ “oldest Asian ally.” What accounts for this, and which one is it? I’ve had a few people ask me about it, and it’s worth briefly exploring.

The United States today has seven main collective security treaties across the world, of which five are in Asia, a point which demonstrates the region’s enduring importance to Washington. These are: the Rio Treaty with Latin American states (which has seen several withdrawals over the past few years); the North Atlantic Treaty Organization (NATO) with Europe; and bilateral alliances with Japan, South Korea, Thailand, the Philippines, and Australia.

Of the Asian security alliances, the one with the Philippines was actually the earliest one to be forged. The U.S.-Philippine Mutual Defense Treaty was signed on August 30, 1951; a few days before the one with Australia and New Zealand (ANZUS) was inked on September 1, 1951 (New Zealand was suspended in 1986); and years before the U.S.-ROK alliance was inked on October 1, 1953 and the U.S.-Japan alliance on January 19, 1960.

Indeed, in terms of security treaty commitments, Thailand is the odd one out among these countries since there was no initial bilateral foundational treaty between Washington and Bangkok. Rather, both countries were signatories of the 1954 Manila Pact of the Southeast Asia Treaty Organization (SEATO), and even though SEATO itself was dissolved back in 1977, the Manila Pact itself remained in force and, along with other bilateral understandings like the Thanat-Rusk communique of 1962 and the 2012 Joint Vision Statement for the U.S.-Thailand Defense Alliance, is considered the wider basis for U.S. security commitments to Thailand.

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This speaks to a broader point often missed about security alliances: though attention tends to be overwhelmingly paid on foundational treaties, they are also often underpinned by a series of more specific agreements and understandings that matter as much, if not more.

But, going back to the original question: given the fact that the U.S.-Philippines security treaty was the first to be signed, why, then, would Thailand be cited as the United States’ oldest ally?

The reason why Thailand is often cited as the United States’ oldest ally in Asia is because both countries had inked a Treaty on Amity and Commerce back in 1833, after they officially established relations in 1818. If one were to view the term ally as not narrowly defined to include just the security realm, but the economic one as well, that would qualify Thailand for this “oldest ally” status.


More broadly, giving the designation to Thailand also acknowledges the reality that U.S. involvement with Thailand goes back much further than it does with the Philippines, even though ties with the latter ended up becoming much deeper far quicker in a more formal sense in the 20th century. The United States presence in Thailand was significant and in some ways quite unique even early on: by the mid-19th century, when formal diplomatic ties were established, U.S. commerce with Thailand had surpassed every country except Britain (before the Civil War intervened), and a level of comfort developed such that by the early twentieth century, Americans were serving as foreign affairs advisers to the Thai king.

U.S. ties to the Philippines, by contrast, really began to be forged once Washington inherited it as a Spanish colony towards the end of the 19th century, which followed a period of occupation and then Philippine independence from Washington in 1946. The legacy of the United States in the Philippines is important to keep in mind because it can animate the relationship even today, as we have seen with some of Philippine President Rodrigo Duterte’s recent comments (See: “Why The Philippines’ Rodrigo Duterte Hates America”).

Given all this, who is right? Is it the Philippines or Thailand who deserves the status of oldest U.S. Asian ally? The answer to that question depends on how narrowly or broadly one defines the term ally, as well as one’s deeper biases with respect to emphasizing more the informal historical ties or deeper, modern ones. A case can easily be made for both, even though it is often stated as fact rather than justified.

Those who have grappled with this question previously — myself included — sometimes try to be helpful either by speaking or writing with more specificity (e.g., Thailand is the United States’ oldest trade and economic ally); or more clarity (e.g., Thailand is often regarded as the oldest U.S. ally on the basis of the 1833 Treaty on Amity and Commerce) when time permits. Even so, none of these details can substitute for a deeper and more granular personal understanding of the origins and evolution of these alliances, which are often grossly simplified today on the basis of assumptions that are more often than not unstated.