The US has issued an apology to Guatemala after the discovery by an American historian, Susan Reverby, that John Cutler, one of the doctors involved in the infamous Tuskegee Syphilis Study in the 1960s, conducted similar experiments on unconsenting Guatemalan subjects twenty years earlier. The Guatemalan experiments, in which the local authorities appear to have been complicit, were carried out on prisoners and mental patients. In some cases prostitutes with syphilis were brought in to infect the men; others had the bacteria poured over abrasions on their penises or injected into their spines.

It happened between 1946 and 1948, during the Ten Years of Spring (1944-54), a period with a cherished place in the national imagination. After the October Revolution of 1944 overthrew General Jorge Ubico, an iron disciplinarian and staunch admirer of Mussolini and Franco, the newly installed junta delivered on their unlikely promise of free and fair presidential elections. A little known writer and teacher, Dr Juan José Arévalo, returned from self-imposed exile in Argentina to be greeted as the nation's saviour and swept to victory. Through his anti-authoritarian political philosophy of ‘spiritual socialism’, Arévalo sought to elevate the moral condition of the people through enhanced legal guarantees of their rights, and to free the country from the yoke of foreign capital (a policy that led, inevitably, to US intervention).

During his two terms in office, Arévalo promoted workers' rights, a huge school-building programme and agrarian reform. But the project came to a shuddering halt in 1954, when Arévalo's successor, Jacobo Arbenz Guzmán, was overthrown in a CIA-sponsored coup. A brutal 36-year civil war followed, with the state enjoying material support from the US (including military training at the School of the Americas) as it tortured, disappeared and murdered 200,000 of its citizens.

So, for Guatemalans, the news that the US was complicit in crimes against humanity in their country is hardly surprising, though the fact that Cutler chose Guatemala precisely because it would permit experiments impossible in the US has made people angry. But above and beyond the revulsion at the details of the experiments, there is the hurt that will be caused by an investigation that in any way tarnishes the memory of Arévalo, one of the best loved men in Guatemala's recent past. Already, right-wing voices are muttering darkly about the 'excesses of Communism’.