Upon handing over the keys to 10 Downing Street in 1963, British Prime Minister Harold Macmillan famously said to his successor Alec Douglas-Home: "My dear boy, as long as you don't invade Afghanistan you'll be absolutely fine." It is advice that too few have followed, including Tony Blair sending the British military to participate in the 2001 U.S.-led invasion.

And yet, the first three British failures in Afghanistan should have been a warning: as the Scottish historian William Dalrymple explains in his book Return of a King : the Battle for Afghanistan, the fourth and most recent Anglo-Afghan war was an extraordinary remake of the first, started in 1839.

For example, the Afghan president from 2004 to 2014, Hamid Karzai, belonged to the same Popalzai minority tribe as the puppet appointed by England in 1839, Shan Shuja ul-Mulk. And Mohammad Shan Khan, the military chief who led the extermination of the British army in 1841, was the heir of the same dynasty (the Hotaki, ruling the Ghilzai, one of the components of the Pashtun people) as the main Taliban ruler, Mullah Omar, ultimately assassinated in 2013.

By hand-picking leaders without knowing the reality of a civilization and history, by pretending to impose a democracy using corrupted chiefs and a foreign army, it was clear that the Western coalition that entered the country after the 9/11 attacks had as little chance as 150 years ago to put in place a stable and legitimate democracy.

Many countries are at risk of turning into dictatorships again.

Of course, Afghanistan is not the only country where it has happened. There have been other such failures, in the transition to a lasting democracy, of dictatorships, or colonized or invaded countries: Algeria, Egypt, Russia, Iraq.

And yet, there have also been examples of success: democracies that were sustainably put in place after periods of dictatorships (Spain, Chile, some parts of the former Yugoslavia); others after the occupation of a foreign power (Germany, Austria, Italy, countries from Eastern Europe, Japan, South Korea); others still after a period of colonization (India, Nigeria, Ivory Coast, Senegal, Ghana), sometimes a long time after colonizers left the land.

And today? Many countries are at risk of turning into dictatorships again; or of not getting through it if the West removes its support: what will happen to Mali, if the French army is removed? To Taiwan if the American military shield is removed? To Lebanon, if the much hoped-for help does not arrive? And even to India, where democracy seems so unstable?What can be done to avoid these disasters? How can a constructive lesson be drawn from the Afghan disaster?

Examples from the past show that a country cannot successfully make a lasting transition to democracy by having it imposed from above by foreign powers, without taking into account its history, its cultural diversity, the existence of a national identity, of a civil society, of the desire to live together, of a powerful group determined to fight to hold it in place; and, without the real liberation of women and young people from the dictatorship of patriarchy.

Then it is clear that it is easier to become a democracy when neighboring countries are already democratic; hence the success, even still fragile, in Eastern Europe, in South America, and in parts of Africa.

We cannot build a democracy if we do not give top priority to education, women's rights, the honest participation of everyone in public decisions and the fight against corruption and nepotism.

Nor when international aid is not conditioned on a move towards democracy and human rights, which almost no donor country and no international financial institution does (with the exception of the OECD, which does the competent and discreet job of training and advising even non-member countries).

Finally, when a democratic system proves itself to be incapable of managing long-term issues, or indulges in petty political debates, any democracy, even ours, is threatened.