A bombing in Bangkok will roil Thai politics

ONLY an hour after a bomb killed at least 20 people on a busy street corner in central Bangkok and injured 140, packed commuter trains were crossing the elevated tracks which overhang the site. At the epicentre of the blast—a railed enclosure around a shrine sacred to Buddhists and Hindus, abutting one of the capital's swankiest hotels—soldiers were moving white-shrouded bodies. A patchwork of white sheets lay scattered across nearby roads and pavement.

Low-level political violence is not uncommon in Bangkok—which is riven by a kind of class war in which two military coups have succeeded in less than ten years—but the attack on August 17th was unprecedented in scale. The blast, caused by a pipe stuffed with TNT, did only relatively moderate damage to the shrine itself and the buildings that surround it. But timed to explode during the evening rush hour, and positioned at an intersection often packed with shoppers and tourists, it was designed to kill and maim a maximal number of bystanders. The dead included visitors from China, Malaysia, the Philippines, Singapore and Indonesia. A five-year old girl was among the injured.

For the moment there are only guesses as to who might be behind the bombing—or what looks like a botched grenade attack on the afternoon of August 18th, at another spot popular with tourists. Some in Bangkok have already blamed Muslim separatists, who have been waging a guerrilla war near Thailand's southern border since 2004; that conflict has cost some 6,500 lives. In April a car bomb which injured several people at a shopping centre on Koh Samui raised the spectre of rebels extending their struggle into well-touristed regions far from their homeland. And there is the worry that they will fall under the influence of international terror groups. But the attack in Bangkok showed a level of force and ruthlessness far beyond anything the rebels have shown.

Another possibility is that the blast is the result of the deep fissures which divide Thailand's national politics. Last year demonstrations led by Bangkok's middle classes helped to oust the populist and democratically elected government of Yingluck Shinawatra, which was replaced by a military junta which retains control of the country. Since then Bangkok has suffered a spate of small but troubling incidents, including a grenade thrown at a courthouse and a small explosion near a railway station, which caused no injuries.

Those looked to be the work of lone extremists, rather than any organised resistance. Indeed, it is difficult to imagine what the junta's opponents could hope to gain from an attack as vicious as yesterday's, which is likely to motivate the generals to tighten the screws. Veterans of the various factional confrontations that have rocked Thailand since 2006—which include a crackdown at a public protest five years ago during which 80 people were killed only a stone's throw from this week's blast—warn that both sides harbour agents provocateurs intent on demonising their opponents.

The bomb also struck a gloomy chord for Thailand's stultified economy, which the junta had pledged to reinvigorate. Growth in tourist arrivals—which had fallen precipitously during political unrest last year—was the only jolly note in a downbeat update released just hours before the explosion. Slow growth poses a serious challenge to the legitimacy of the junta, which had promised it could manage Thailand more effectively than the politicians it ousted. Rumour has it that Prayuth Chan-ocha, the prime minister, will sideline his principal economic advisor in a cabinet reshuffle.

The bomb will also hobble Thailand in its way back to democracy, on which it was making little progress. That may well suit the generals, who probably wish to stay in power through the potentially tricky succession which will follow the death of the aged and ailing King Bhumibol Adulyadej. Having talked of holding fresh elections sometime this year, in recent weeks the self-appointed leadership has been hinting that polls are unlikely before 2017. Lately conservatives in Bangkok have lobbied for the army to extend its rule formally, on the ground that Thailand's stability remains at risk. Today more people will agree with them.