The recent escalation of protest action by the People’s Alliance for Democracy (PAD) has taken Thailand to the brink of civil breakdown. Swathed in King Bhumibol Adulyadej’s royal yellow, the protesters have forced the government of Samak Sundaravej to declare a state of emergency.

There is real fear that one wrong move could send the situation spiralling out of control. A violent clash on Monday night between pro- and anti-government mobs, which left at least one of the combatants dead and scores injured, is an ominous sign of what may lie ahead.

The PAD have insisted that they won’t back down until Samak’s government resigns. They want to scrap the result of the December 2007 election. They don’t want another election because they know that Samak and his allies would win again. What they want instead is a system where 70 percent of the parliament is appointed. Under their version of “Thai-style” democracy, appointment and patronage would trump any electoral mandate.

Having raided the national broadcaster, laid siege to Government House and taken over airports and other critical infrastructure, their rebellion is seeking, unashamedly, to provoke a heavy-handed government response.

Sidestepping this provocation, Prime Minister Samak and the security apparatus he still commands have, thus far, shown commendable restraint. The police have been ordered to deal with the protesters as gently as possible. Army units deployed to prevent further clashes between rival groups of protesters have been armed only with shields and batons. This approach has strengthened the legitimacy of the government but at the same time it seems to be driving the PAD to ever-more provocative forms of protest action and civil disruption.

The PAD protests in the name of the king. Since their street campaign against Samak started in May this year, the majority of the protesters have proudly worn yellow shirts. Yellow is the king’s colour. Under banners like “We fight for the king” they have sought to position themselves as a legitimate expression of royal will. They present themselves as defenders of the monarchy against politicians like Samak. And they launched the current wave of anti-government rebellion on the birthday of the king’s most trusted political and military ally, Privy Council chairman General Prem Tinsulanonda.

So how has the king responded to this cooption of his royal brand? Worryingly, while his majesty’s government is under siege, the king and his privy councillors have maintained a detached public silence.

The world’s longest reigning monarch, King Bhumibol gives regular speeches that are widely reported across his kingdom. Before his birthday on 5 December each year there is an eagerly awaited instalment of royal wisdom. At other times of the year, to audiences of government ministers, judges or other senior officials, the king imparts sporadic messages of unity, fealty and diligence. In his speeches the king also grasps the opportunity to introduce pet policy proposals, such as the widely trumpeted sufficiency economy approach.

He usually stays away from politics but the king is interventionist when it suits.

Speeches to the judiciary in April 2006 ultimately signed the death warrant for the government of Thaksin Shinawatra. The judges saw fit, with royal imprimatur, to destroy the government’s electoral mandate declaring that Thaksin’s snap election was null and void. After the coup that removed Thaksin, the king’s 2006 birthday speech lavishly endorsed the military government of privy councillor Surayud Chulanont.

What the king says undoubtedly matters. However what goes unsaid can be just as important.

It was only last month that Thai and Cambodian forces stood eyeball to eyeball along their shared border. Nationalist passions, stoked by the People’s Alliance for Democracy protests over Cambodia’s World Heritage application for a temple close to the border, almost led to war between the two nations. The king stayed quiet.

And now the People’s Alliance for Democracy has shifted its attention to bringing down the Samak government.

The king is silent again. Not one word of disavowal. Not one attempt to restrain the mob that protests in his name.

That silence carries great risks. In May 1992 members of an anti-military people’s movement were gunned down on the streets of Bangkok. That bloodbath was only stopped when the king broke his silence.

The enduring image of that tumultuous period is of the opposing sides on their knees, taking a royal scolding. It was, for the palace histories, the king’s crowning moment as national saviour. But according to his unofficial biographer, Paul Handley, “there is the problem that Bhumibol acted only three days after the first demonstrators were killed”.

Today the king should not wait for more ordinary Thais to suffer the consequences of brinksmanship. The People’s Alliance for Democracy is goading the Samak government to over-react. With the real possibility of more bloodshed in Bangkok in the days ahead, the king’s silence is baffling. His lifelong reservoir of charisma is no good to his people if he does not call off the anti-democratic provocateurs acting in his name.