The massive yellow crowd that assembled in Bangkok last week to mark King Bhumipol’s birthday leaves no doubt that he remains an enormously potent figure in Thai public life.

In recent years Bhumipol has endured enormous challenges: the coup of 2006 focussed attention on his political role; yellow-shirt provocations sullied the royal brand; the violent suppression of the red-shirts sparked an unprecedented out-pouring of anti-royal sentiment; harsh prison sentences for lese-majeste have attracted domestic protest and international scorn; and failing health has seen Bhumipol confined to hospital since 2009.

But despite all these challenges, royal power and charisma endure. “Highly revered” is a much overused cliché in accounts of Thailand’s king, but like many clichés it contains a significant degree of truth. There is only one other person who could mobilise such a crowd on the streets of Bangkok – Thaksin Shinawatra.

Some observers may want to dismiss this display of royal affection as the product of ideological manipulation and coercion. No doubt, the king’s popularity owes much to decades of carefully controlled public relations. Thailand’s lese majeste laws leave no room for frank public assessment that could contribute to a balanced view of the monarch. Many Thais are constrained by a legal system of affection by fiat. Subtle and not-so-subtle pressures are probably also placed on some employees, students and public officials to don yellow shirts and attend royal birthday events.

Nevertheless, it would be a mistake to place too much weight on these negative assessments which, unconsciously or otherwise, mirror the disparagement of pro-Thaksin red-shirt protesters as “buffaloes” and paid stooges. Political attitudes are always formed within networks of power, persuasion and coercion and I don’t see anything particularly inauthentic about the esteem in which the king is held by many Thais. The blind spot in royalist ideology is not the claim that King Bhumibol is a sacred figure deserving of respect. Rather, the blind spot–and it can be a very lethal blind spot indeed–is the view that the king is an ultimate representation of virtue and merit and that his actions are beyond question.

Thais are pragmatic and evaluative in their approach to power and the monarchy is readily incorporated into local panoplies of spirits, corporations and politicians.

Given the resilience of affection for the king, it is no surprise that Prime Minister Yingluck Shinawatra has baulked at tackling reform of the lese majeste law. Her government has been rightly criticised for maintaining the royal family’s draconian legal protections. Her inaction on this iconic issue has been a major disappointment.

But Yingluck is a politician. The government won’t move on lese majeste while the cost-benefit score is so heavily weighted in favour of inaction. Reformists already support Yingluck; they are disappointed and angry but they have no one else to turn to. To embark on meaningful reform would provoke the ultra-royalists and potentially galvanise opposition among a much wider segment of society with royalist sympathies. It wouldn’t threaten Yingluck’s dominant electoral position but reform is certainly not a vote winner.

The challenge for human rights campaigners is to build a grass roots reform campaign that promotes the view that affection and evaluation are compatible. Unfortunately, this is likely to be very difficult during the reign of King Bhumipol. But when King Vajiralongkorn is on the throne the balance between affection and evaluation will shift dramatically and reform will be a much easier task.

Last week’s massive rally in support for the king points to an important weakness in Thai political life. At present, those with strongly royalist sentiments lack a political vehicle that has a chance of winning power by democratic means. The Democrat Party is their natural choice. But the Democrats have not won an election in their own right since 1992. Economic growth, demographic shift and social transformation since then mean that they are unlikely to win again. Thailand’s royalist party is, quite simply, unelectable.

As a result, legitimate and authentic royalist sentiment will increasingly be channelled in extremist directions, producing civil society perversions like Pitak Siam and unstable demagogues like Sondhi Limthongkul. In this sense, the weakness of the Democrat Party poses a real risk to Thai democracy.

Despite the challenges it has faced in recent years, royalism in Thailand is alive and well. It desperately needs strong institutions that can help domesticate and democratise its unpredictable power.