The polarisation of the debate around WikiLeaks is pretty simple, really. Of all the governments in the world, the United States government is the greatest threat to world peace and security today. This is obvious to anyone who looks at the facts with a modicum of objectivity. The Iraq war has claimed certainly hundreds of thousands, and, most likely, more than a million lives. It was completely unnecessary and unjustifiable, and based on lies. Now, Washington is moving toward a military confrontation with Iran.

As Lawrence Wilkerson, former chief of staff to Colin Powell, pointed out in an interview recently, in the preparation for a war with Iran, we are at about the level of 1998 in the buildup to the Iraq war.

On this basis, even ignoring the tremendous harm that Washington causes to developing countries in such areas as economic development (through such institutions as the International Monetary Fund and World Trade Organisation), or climate change, it is clear that any information which sheds light on US "diplomacy" is more than useful. It has the potential to help save millions of human lives.

You either get this or you don't. Brazil's president Lula da Silva, who earned Washington's displeasure last May when he tried to help defuse the confrontation with Iran, gets it. That's why he defended and declared his "solidarity" with embattled WikiLeaks founder Julian Assange, even though the leaked cables were not pleasant reading for his own government.

One area of US foreign policy that the WikiLeaks cables help illuminate, which the major media has predictably ignored, is the occupation of Haiti. In 2004, the country's democratically elected president, Jean-Bertrand Aristide, was overthrown for the second time, through an effort led by the United States government. Officials of the constitutional government were jailed and thousands of its supporters were killed.

The Haitian coup, besides being a repeat of Aristide's overthrow in 1991, was also very similar to the attempted coup in Venezuela in 2002 – which also had Washington's fingerprints all over it. Some of the same people in Washington were even involved in both efforts. But the Venezuelan coup failed – partly because Latin American governments immediately and forcefully declared that they would not recognise the coup government.

In the case of Haiti, Washington had learned from its mistakes in the Venezuelan coup and had gathered support for an illegitimate government in advance. A UN resolution was passed just days after the coup, and UN forces, headed by Brazil, were sent to the country. The mission is still headed by Brazil, and has troops from a number of other Latin American governments that are left of centre, including Bolivia, Argentina and Uruguay. They are also joined by Chile, Peru and Guatemala from Latin America.

Would these governments have sent troops to occupy Venezuela if that coup had succeeded? Clearly, they would not have considered such a move, yet the occupation of Haiti is no more justifiable. South America's progressive governments have strongly challenged US foreign policy in the region and the world, with some of them regularly using words like imperialism and empire as synonyms for Washington. They have built new institutions such as UNASUR to prevent these kinds of abuses from the north. Bolivia expelled the US ambassador in September of 2008 for interfering in the country's internal affairs.

Is it because Haitians are poor and black that their most fundamental human and democratic rights can be trampled upon?

The participation of these governments in the occupation of Haiti is a serious political contradiction for them, and it is getting worse. The WikiLeaks cables illustrate how important the control of Haiti is to the United States. A long memo from the US embassy in Port-au-Prince to the US secretary of state answers detailed questions about Haitian president Rene Preval's political, personal and family life, including such vital national security questions as "How many drinks can Preval consume before he shows signs of inebriation?" It also expresses one of Washington's main concerns:

"His reflexive nationalism, and his disinterest in managing bilateral relations in a broad diplomatic sense, will lead to periodic frictions as we move forward our bilateral agenda. Case in point, we believe that in terms of foreign policy, Preval is most interested in gaining increased assistance from any available resource. He is likely to be tempted to frame his relationship with Venezuela and Chávez-allies in the hemisphere in a way that he hopes will create a competitive atmosphere as far as who can provide the most to Haiti."

This logic is why they got rid of Aristide – who was much to the left of Preval – and won't let him back in the country. This is why Washington funded the recent "elections" that excluded Haiti's largest political party, the equivalent of shutting out the Democrats and Republicans in the United States. And this is why Minustah is still occupying the country, more than six years after the coup, without any apparent mission other than replacing the hated Haitian army – which Aristide had abolished – as a repressive force.

People who do not understand US foreign policy think that control over Haiti does not matter to Washington, because it is so poor and has no strategic minerals or resources. But that is not how Washington operates, as the WikiLeaks cables repeatedly illustrate. For the state department and its allies, it is all a ruthless chess game, and every pawn matters. Left governments will be removed or prevented from taking power where it is possible to do so; and the poorest countries – like Honduras last year – present the most opportune targets. A democratically elected government in Haiti, due to its history and the consciousness of the population, will inevitably be a left government – and one that will not line up with Washington's foreign policy priorities for the region. Thus, democracy is not allowed.

Thousands of Haitians have been protesting the sham elections, as well as Minustah's role in causing the cholera epidemic, which has already taken more than 2,300 lives and can be expected to kill thousands more in the coming months and years. Judging from the rapid spread of the disease, there may have been gross criminal negligence on the part of Minustah – that is, large-scale dumping of fecal waste into the Artibonite river. This is another huge reason for the force to leave Haiti.

This is a mission that costs over $500m a year, when the UN can't even raise a third of that to fight the epidemic that the mission caused, or to provide clean water for Haitians. And now the UN is asking for an increase to over $850m.

It is high time that the progressive governments of Latin America quit this occupation, which goes against their own principles and deeply-held beliefs, and is against the will of the Haitian people.