With defence expenditures directly linked to the country's development, Prime Minister Prayut Chan-o-cha is obliged to consider both the current economic malaise and his government's relatively limited funds in making a decision on buying expensive new equipment for the military.
If the former Army commander requires guidance on the impact of military spending on a nation's fiscal health and ultimately the wellbeing of its people, he need only refer to crisis-hammered Greece.
The North Atlantic Treaty Organisation has projected that Greece will this year spend 2.4 per cent of its GDP on defence, a 0.1-per-cent increase from 2014, when the Mediterranean country's debt represented 175 per cent of GDP and its economy shrunk by 3.3 per cent.
With a population of just 11 million, Greece is the largest importer of weapons and other military equipment from elsewhere in Europe, particularly from Germany, home to a mighty defence manufacturing industry.
The imports put small, struggling Greece in the same league as powerhouses like China and India in terms of buying weapons from abroad.
Greece's military spending is the highest in the European Union, and in fact many analysts cite its devotion to this ersatz show of strength as a key factor behind its appalling indebtedness.
Between its most recent military coups, in 2006 and 2014, Thailand's defence budget far more than doubled, from Bt81 billion (S$3 billion) re-coup 2005 to Bt180 billion. The military-led government is now mulling a 2016 defence budget of Bt207 billion, marking a 7-per-cent hike over this year and representing nearly 8 per cent of total state expenditures, as well as 1.5 per cent of GDP.
As usual, the military is maintaining that more money is needed to protect national interests, but protect them from what? As usual, none of its leaders has identified a specific threat or threats that Thailand faces or might face in this combat-free region.
Clearly the Navy was paying no heed to the country's current economic weakness and the global situation as a whole when, last Thursday, it formally sought permission to purchase three submarines from China, total price tag Bt36 billion. This came immediately in the wake of Prime Minister Prayut's announcement that our universal healthcare scheme must be revamped.
Healthcare for needier citizens is in jeopardy because the government has insufficient funds.
Objections poured in to the Navy's plan, even from several pro-military politicians and academics, who insist there is no pressing need for Thailand to have such formidable and expensive craft. It's not as though our Southeast Asian neighbours with submarines - Vietnam, Malaysia, Singapore and Indonesia - are posing challenges or gaining any military advantage at sea.
Peacetime military spending must always be subjected to the keenest critical scrutiny, and in times of dire economic conditions there is no leeway at all to build up military strength. Our coffers and our resources are clearly inadequate to the proposed purchase at this time, with its minimal, perhaps non-existent, return value to the taxpayer.
Security experts are agreed that the chance of conventional warfare in this region is highly remote in the foreseeable future.
The countries with the greatest maritime strength are all dedicated members of the Association of Southeast Asian Nations, through which peace and mutual economic development trump any former animosities.
The genuine threats facing Thailand and its neighbours take the form of natural disasters, marine piracy and smuggling - all of which require quick-response action best provided by aircraft and surface ships. It's impossible to imagine any role in such crises for a submarine that's costly to operate and has only enough room aboard for the crew.