Preparations are under way in the Democratic Republic of Congo for celebrations to mark 50 years of independence in June. The Congolese government has reportedly set aside $2 million for the festivities. Guests of honour will include a high-level Belgian delegation, headed by King Albert II, who will be on his first official visit to the former colony.

With these festivities in the air, how has the first half-century of independence been for the Democratic Republic of the Congo?

While it’s difficult to sum up the past 50 years, one thing that can be said with some confidence is that they have been troubled – from the western-backed murder of independence leader Patrice Lumumba, through the long and repressive Mobutu dictatorship, to the Second Congo War, known as Africa’s World War, not only because of its being the deadliest conflict since the second world war but also because it involved seven foreign countries.

Today, a stability of sorts has descended upon the country with its elected dictator, Joseph Kabila, although fighting continues in a number of provinces of this vast country, particularly in the east.

Despite its enormous mineral wealth, the DRC is one of the poorest countries in the world, largely due to the uncontrolled plundering of its resources. With a per-capita GDP of around $100 per year, it comes close to the bottom of the well-being league, though its human development index is constantly rising.

In fact, Congo is a classic example of the fragile African state. So, what lies behind this fragility?

A key factor is a failure of leadership on a monumental scale. Political corruption, coupled with weak state institutions, has ensured that the main function of Congolese politics, like in many other African countries, is to serve the private ends of the ruling elite.

“The political class in Congo is shit,” Joseph Nzau, a 55-year-old Congolese professional based in Brussels, told me in no uncertain terms. “Politicians don’t have the common good in mind. They want to enrich themselves first and their clans second.”

Whereas political corruption may skim some of the cream off the top of the pie in countries with effective governance, in places like the DRC, it gobbles up the lion’s share of the cake, as attested to by the vast fortunes Mobutu and his cronies accumulated or squandered.

But should Congo’s political class cop the entire blame? Well, there are certainly other factors at play. The DRC is about the size of western Europe, but the country has a population that is smaller than Germany’s and yet is divided into some 250 ethnic groups speaking an equivalent number of languages. Governing such a huge and diverse land mass, with a relatively low population density, not to mention poor infrastructure and a state that is weaker than probably even the smallest European states, is no easy matter.

Much as apologists for Europe’s colonial legacy and those afflicted with selective amnesia would like to believe, the reality is that Congo’s colonial experience, as in so many other post-colonial states, has caused deep and lasting scars, and very much handicaps the modern state. “The situation of Congo today is a consequence of Belgian colonisation,” Nzau says, expressing a common Congolese perception.

But this link between European colonialism and the current turmoil in much of sub-Saharan Africa is not just a case of Africans looking for someone else to blame, as is so often claimed. In fact, the same link was explicitly made in last year’s European Report on Development. “The scramble for Africa … is a natural candidate for the historical origin of the fragility plaguing many sub-Saharan African countries,” the report stated.

But why should such a relatively short sojourn have such a profound impact? In the case of Congo, part of the reason is that there was a centuries’-long prelude. Prior to direct rule, most of central Africa was depopulated as a consequence of the European slave trade to the west and, to a lesser extent, the Arab slave trade to the east. This, for example, helped accelerate the eventual collapse of the once-powerful indigenous kingdom of Kongo (which had different borders to the contemporary DRC).

The ruler, Nzinga Mbemba Affonso, an early convert to Christianity, wrote regularly to the king of Portugal to complain about the effects of the slave trade on his subjects:

Each day the traders are kidnapping our people – children of this country, sons of our nobles and vassals, even people of our own family. This corruption and depravity are so widespread that our land is entirely depopulated. We need in this kingdom only priests and schoolteachers, and no merchandise, unless it is wine and flour for mass.

Undoubtedly, the worst chapter in Congo’s history was when the country became the personal property of King Leopold II, who wanted a domain to match his ego. The king infamously described Belgium as “petit pays, petits gens” (“small country, small people”) due to his subjects’ lack of appetite for empire – unsurprising given that they had been ruled for centuries by foreign powers, including the Spanish, the Habsburgs, the French and the Dutch.

Jealous that he did not preside over an empire like his cousin, Queen Victoria, across the Channel, Leopold spent years in search of a land that he could transform into his personal fiefdom. With the help of the dodgy Welsh-born American explorer and journalist Henry Stanley (born John Rowlands), Leopold set his sights on a part of Africa unclaimed by the other European powers which he eventually gave the name Congo Free State. During his private rule, an estimated 2-15 million Congolese died through forced labour and other forms of exploitation.

International outrage and one of the first major human rights campaigns in modern history led to the Belgian government taking Congo off Leopold’s hands and annexing it. Although the worst human rights abuses ended, the main priority of the Belgian Congo, despite Belgium’s earlier reluctance to enter the colonial game, remained the exploitation of the country’s mineral wealth for the benefit of the Belgian economy.

During the period of direct rule, the European institutions and structures that were brought in took little account of local culture and conditions. After independence, rather than reform the state, local leaders simply took it over, alienating themselves from the population.

The 50th anniversary of independence should give Belgians and Congolese pause for thought. In the coming half-century, the Congolese need to overcome the legacy of the past and take command of their future. For their part, Belgians need to recognise that their colonial legacy is not just an issue for historians but that it helped create the current mess.

This is the extended version of an article which appeared in the Guardian newspaper’s Comment is Free section on 21 April 2010. Read the full discussion here.