The latest blast in Bangkok occurred May 22 inside a military-run hospital in the central part of the city, injuring at least 21 people. According to Bangkok police, a timer-activated pipe bomb packed with nails was hidden inside a vase in a waiting room where a number of retired senior military officers were awaiting treatment. No one has claimed responsibility for the attack, but a government spokesman blamed opposition elements attempting to discredit the junta.

The incident itself was relatively minor; the device did not appear to be designed to cause major damage to the building, and few of the injuries are believed to be serious. But considering the timing and target set of the bomb, it largely fits the profile of what are known in Thailand as "political intimidation attacks" — generally, small bombs striking symbolically rich targets in ways not intended to cause mass carnage — that become common during periods of political unrest. In fact, the May 22 attack appears to be the third such incident in just over a month. On April 5, two people were injured by a nearly identical PVC pipe bomb outside the old Government Lottery Office in Bangkok. And on May 14, two more people were injured by another pipe bomb outside Bangkok's National Theater, near where late King Bhumibol Adulyadej will be cremated later this year.

Thai authorities generally either ignore or downplay the significance of political intimidation attacks to project calm and avoid legitimizing the cause espoused by the culprits. But the attacks appear to have put the junta on edge. For example, rather than dismissing the May 14 incident as an accident (as police initially did) or blaming it on feuding local criminal elements (a common response), the junta blamed it on opponents of the military government and visibly boosted security across the capital. Following the hospital bombing, Thai Army Commander-in-Chief Gen. Chalermchai Sitthisart linked all three attacks and called the hospital bombing Thailand's "worst-ever." A security adviser to the junta said a professional network was likely behind them.

Part of the pretext for the military's 2014 coup and continued iron-fisted rule, after all, has been the need to restore order to Thailand after nearly a decade of often-violent political unrest and policymaking paralysis. And Thailand has indeed been relatively calm over the past three years (with the notable exception of the low-grade insurgency waged by Malay-Muslim rebels in Thailand's southernmost provinces, who are unlikely to have been involved in the attacks in Bangkok). The junta has successfully clamped down on dissent and has largely neutralized hard-line supporters of former Prime Minister Thaksin Shinawatra. Over the past six months, in particular, the junta has been able to leverage the death of widely beloved King Bhumibol in October to maintain order, even while further delaying its long-promised return to elections (currently penciled in for the end of 2018, at the earliest).

But the further Thailand gets from the king's death, the more likely its currents of discontent are to resurface. The junta is attempting to implement a form of "managed democracy" that empowers unelected establishment institutions such as the courts and, in particular, the military at the expense of civilian politicians. Thailand is also trying to kick-start a massive long-term economic development agenda that future civilian governments would not be allowed to alter — thus depriving them of lucrative sources of patronage with which to build powerful political coalitions. Meanwhile, under new King Maha Vajiralongkorn, a contentious figure who lacks his father's esteem, the state will be attempting to remake its relationship with a monarchy that can no longer play the stabilizing role it did under Bhumibol.

For the junta, each endeavor is fraught with potential to spark broader power struggles, including within the divided military. Thaksin demonstrated how civilian politicians could challenge the military-backed establishment by uniting the interests of disaffected upcountry voters with those of business blocs and factions of security forces keen for more political influence and rewards. At the same time, the new king is attempting to carve out a power base independent of the junta, opening opportunities for new alliances. The fault lines abound.