It's a double hit: first the subsidies, then aid to mitigate the damage. In 2005 I travelled from Bamako, the capital of Mali, on one of the few roads and then for hours into the interior across a harsh arid landscape until I came to Beleco, a village in the cotton-growing district of Fana. There Yayas Sangare told me that his family had grown cotton for generations. He works in the field with his nine sons all day, every day. Thirty per cent of Mali's people depend on cotton for their livelihood. It helps to pay for hospitals, houses and schools. Success pays taxes.
Malian farmers produce high-quality cotton at competitive prices; the production costs are three times lower than in the US. Yet despite all these advantages people such as Mr Sangare suffer because of the enormous subsidies that the US and some EU cotton growers receive.
There are 25,000 cotton farmers in the US compared with more than 10 million in West Africa. In recent years US cotton producers have been given $5 billion of taxpayers' money - more than the combined earnings of all Mali's cotton farmers. These subsidies artificially depress the price of cotton on world markets.
The farmers I met in Beleco know exactly why cotton prices are so low. "We can compete with American farmers but we cannot compete with their subsidies," Magnan Fane said.
These subsidies are a fraud on the taxpayers of the US and of the EU, which is guilty of the same support for its cotton growers through the CAP. In recent years total subsidies have been higher than the value of the cotton produced. Growing cotton costs the US money. It would have been better not to have grown it all. Indeed the US taxpayer is hit twice over - first for the subsidies to farmers and second for aid programmes to mitigate some of the damage done by those subsidies in West Africa.
The recent turmoil in Mali has underlined the importance of tackling the root causes of conflict and instability - first, by military means and, second, by addressing the poverty that is in part caused by unnecessary, demeaning trade barriers.
In his second inaugural this week, President Obama spoke eloquently about the need to tackle insecurity and poverty. He said: "We must be a source of hope to the poor, the sick, the marginalised, the victims of prejudice ... because peace in our time requires the constant advance of those principles that our common creed describes: tolerance and opportunity, human dignity and justice."
In the week when MEPs voted to make the excesses of the CAP even worse let us hope for Mali's sake that the President's eloquent words are turned into real action on the ground.
Andrew Mitchell was International Development Secretary, 2010-12