This week in Rome, Mohammed Zahir Shah, the former king of Afghanistan, agreed with the Northern Alliance, the opposition force to the Taliban, to convene a loya jirga. This grand assembly of Afghan tribal leaders would initiate a process to create a transitional government and eventually hold elections.

The US, the United Nations and others are placing great store on the success of the enterprise. But at the beginning of the 21st century, how much can a king be expected to achieve in one of the world’s most fractured countries and sensitive regions?

Ten years ago, an exiled king stepped in to fill the breach in a similar situation in Cambodia, south-east Asia. King Sihanouk’s role in Cambodia was strikingly similar to that envisaged for Zahir Shah in Afghanistan. On the basis of a 1991 peace agreement backed by the UN and regional powers, he was expected to be an arbiter of state unity.

The Cambodian experience offers instructive lessons for the road ahead in Afghanistan. Given the constellation of interested parties—including Pakistan, China, Russia, Iran, India and the central Asian states, in addition to the US and its allies—nation-building in Afghanistan will have to be an international affair.

In Cambodia, the UN played the pivotal role in supervising elections, rebuilding the economy and resettling refugees. It would probably have to play the same role in Afghanistan. But its involvement would be much greater, more expensive, and take longer than in Cambodia, where the UN’s mandate extended for only 18 months after the peace deal and cost $2bn.

A political settlement in Afghanistan would also have to address the question of a permanent government, and potentially the creation of a new constitution. That would be a difficult exercise in a country with so many political, ethnic and religious divisions.

Refugee resettlement in Afghanistan would pose a logistical and political challenge of gargantuan proportions. Cambodia had only about 300,000 refugees on the border with Thailand, but the refugee crisis from the Soviet invasion of Afghanistan involves 6m people. There are still 2m refugees in Pakistan and Iran, and 1.5m more are expected from the current upheaval. In addition, there is a large expatriate community from earlier waves of emigration that may eventually seek to return.

As for creating a new government on the basis of the former king and the Northern Alliance, the Cambodia case illustrates how easy it is to indulge in wishful thinking and exaggerate the strength of resistance coalitions and their internal support. In Cambodia, as now in Afghanistan, opposition forces controlled only a sliver of territory before the conclusion of a peace agreement. Cambodia’s KPNLF, part of the resistance coalition backed by the US, in effect disappeared as a political force on its return.

The Taliban may also be difficult to eradicate. It has laid down deep roots and shaped the political infrastructure. In Cambodia, elements of two former regimes—the Khmer Rouge and the Hun Sen government—signed the Paris peace agreement and were given a chance to participate in a new government. The Khmer Rouge withdrew when it became clear it would not win the elections, but has only now been eliminated as a political force after 10 years. Hun Sen was incorporated into the Cambodian coalition government and won the upper hand. The first local elections that may finally reduce Hun Sen’s influence will take place next February.

However, groups such as the Taliban are highly dependent on the support of their patrons. Here, the case of Cambodia has some encouraging lessons for Afghanistan. In Cambodia, the fact that China and Vietnam—the primary supporters of the Khmer Rouge and Hun Sen respectively—withdrew their support and sponsored the peace agreement and new elections was critical to success.

Afghanistan, like Cambodia, is a relic of the cold war, a proxy battleground for past ideological struggles. Instability in Cambodia in 1991 became an obstacle to new political and economic relations in south-east Asia, just as chaos in Afghanistan now impedes development in central and south Asia. Pakistan has played a pivotal role in supporting the Taliban, and Pakistan and other regional states that originally chose sides in the Afghan conflict should now withdraw that support and guarantee a final settlement.

Finally, kings have their limitations. In Cambodia, Sihanouk was able to play a balancing role only in extreme moments. He failed to prevent a 1997 coup by Hun Sen that toppled his son and successor. He has remained largely a figurehead in Cambodian politics, albeit a respected one. While kings can provide a powerful symbol, the machinations of internal and external politics determine the outcome of events. Ten years on, Cambodia is still groping toward stability. Afghanistan has not yet begun.