RESIDENTS of Bangkok, which has seen more than its share of political unrest, sometimes seem hard to shock. But the bomb which exploded at the Erawan shrine in Thailand’s capital on August 17th, killing more than 20 people and injuring about 100, has unnerved and bewildered in equal measure. It was timed to explode at a packed intersection during the evening rush hour. Grainy video footage just before the blast shows a young man slipping off a rucksack near the site. Some blame Muslim separatists in Thailand’s deep south. Others say it is “red-shirt” supporters of the populist government driven out in a coup last year.

Nothing is clear, except for one thing: the bomb has shattered the illusion of safety which the junta that seized power in May last year wished to foster. The generals justified their coup by claiming that they alone could protect Thais from the violence that had sporadically erupted during a decade of squabbles between the country’s democratically elected governments and Bangkok’s conservative elites. By targeting tourists, the bombers have also undermined the generals’ claims to be boosting Thailand’s flagging economy. With shrinking exports, dwindling foreign investment and high household debt, the economy badly needs visitors to come to Thailand and spend.

Seeking legitimacy—and perhaps grasping for ways to paper over rifts in Thai society, which its own coup has widened—the junta has spent much of its time in power pepping up enthusiasm for a monarchy that is embodied in the 87-year old king, Bhumibol Adulyadej. Just two days after the blast General Prayuth Chan-Ocha, the prime minister and coup leader, attended the opening in Hua Hin of a new park containing the colossal statues of seven long-dead Thai kings, built by the army at a cost of about $20m. The bronze monarchs are not entirely out of keeping with a sprinkling of chintzy attractions that already surround Hua Hin, a resort with royal connections. But they are an oddly Soviet spectacle.

More grimly, in the past 15 months the junta has presided over a big increase in the number of people charged with insulting the sovereign, a grave offence in Thailand. Punishments have also grown more harsh. Thai academics and foreign residents are growing increasingly concerned about what they say. Thailand’s usually rambunctious users of social media are also growing more cowed. On August 7th a 29-year-old mother of two was sentenced to 28 years in jail for posting supposedly anti-royal material on Facebook; the same day a travel agent was handed 30 years for the same offence.

The draconian sentences even earned a rebuke from the UN. But they were doubtless a useful warning to opponents, including many students, who had been airing grievances more openly as the junta appeared to be settling in for the long haul. Having first talked of holding fresh elections as early as this year, it now hints that no poll is likely until at least 2017. A draft new constitution, to be considered next month, will anyway see future civilian governments subjugated to a suite of appointed councils.

Few observers reckon the junta will consider ceding any control until well after the death of King Bhumibol, who has long been ailing. Indeed the desire to control what may prove to be a turbulent succession may have been the primary motivation for last year’s coup. The palace recently admitted that the sovereign, who has not been seen in public for months, is getting treatment for a build-up of water on the brain. The crown prince, Maha Vajiralongkorn, is unpopular; worse for the elites, he may still be friendly with Thaksin Shinawatra, a populist former prime minister whose parties the army has twice kicked out of power. For years rumours have persisted that after the king’s death, palace insiders might aim to elevate the prince’s less divisive sister, Sirindhorn, to the throne instead.