Young Rwandan refugees plead with Zairean troops on Aug. 20, 1994, to allow them across a bridge separating Rwanda and Zaire, where their mothers had crossed moments earlier before the soldiers closed the border. At least 500,000 people were killed in the 1994 genocide in Rwanda. (Jean-Marc Bouju/AP)

This week marks 21 years since the onset of the 1994 Rwandan genocide, in which more than 500,000 people, mostly members of the Tutsi ethnic minority, were slaughtered. While the Rwandan genocide has become an iconic symbol of the need for international humanitarian intervention, at the time, governments were very slow to react. In the aftermath of the genocide, as the extent of the devastation become clear, governments said they were unaware of what was happening. A growing body of evidence, however, demonstrates what those of us living in Rwanda in the period before the genocide saw clearly — there were ample warnings that violence was approaching. The lack of political will, rather than the lack of information, prevented the world from acting to stop the killing.

When I arrived in Rwanda in May 1992, the political climate was abuzz with optimism. The regime of President Juvenal Habyarimana had legalized opposition parties the year before under pressure from a growing domestic pro-democracy movement as well as foreign diplomatic pressure. Popular protests that began in late 1991 pushed Habyarimana to go a step further and name a multiparty government led by an opposition prime minister that took power in April 1992. It seemed open elections might soon be held and Habyarimana himself might soon be pushed out.

Over the next 12 months, however, I watched as Rwanda slid steadily into violence. As I conducted fieldwork for my dissertation on religion and politics (later published as Christianity and Genocide in Rwanda), I found ethnic and political tensions increasing sharply, while fears about the country’s future spread rapidly. Although Habyarimana instituted political reforms to appease critics, he and his supporters simultaneously worked to undermine the effect of the efforts. Because opposition parties were now part of the government, Habyarimana was able to blame them for the country’s rapidly declining economy and growing insecurity. At the same time, opposition politicians newly integrated into the government began to complain that they lacked real power, as supporters of Habyarimana’s ruling party kept real decision-making in their own hands.

The president’s allies, meanwhile, sought to retake political initiative by fomenting ethnic conflict. They portrayed themselves as defenders of the country’s ethnic Hutu majority and painted the opposition politicians as allies of the Tutsi minority that had exploited the Hutu during the colonial era. With the largely Tutsi Rwandan Patriotic Front attacking the country since October 1990, claims that the Tutsi were seeking to retake control of Rwanda and oppress the Hutu resonated with many, particularly as the RPF began to make advances on the battlefield. A series of small-scale attacks against Tutsi in various parts of the country were designed to look like spontaneous popular actions, but an international human rights mission led by Human Rights Watch demonstrated in early 1993 that they were organized by government officials seeking to heighten ethnic tensions in the country.

Within a few months of my arrival in Rwanda, many people I interviewed expressed growing doubts about the political situation. They complained that the opposition politicians were no better then the ruling regime, and many expressed fears at the chaos that democratization seemed to be bringing to the country. Tutsi friends and colleagues began to express concerns for their safety. An RPF attack in February 1993 that nearly reached the capital, Kigali, sent particular waves of fear and uncertainty through the population. By the time I left Rwanda in April 1993, pessimism and dread had taken over the political stage. I left Rwanda fearing that ethnic and political violence was imminent.

In documents released Monday as part of a report by the U.S. Holocaust Museum on preventing genocide, we now know that warnings about the potential for extensive ethnic violence in Rwanda were already being broadcast to Washington by U.S. diplomats at the very time that I was becoming increasingly concerned on the ground. In a report in Foreign Policy, Colum Lynch details the earliest cable warning of possible ethnic violence from the U.S. Embassy’s deputy chief of mission sent from Kigali in August 1992. In Leave None to Tell the Story, the HRW report that I helped to research and write under the direction of the late Alison Des Forges, we devoted an entire chapter to warnings about the potential for genocide in Rwanda between November 1993 and April 1994, trying to disprove the claim of many diplomats that they didn’t know what was happening in Rwanda. These new documents now show that the warnings went back even further, to the George H.W. Bush administration. We now know that Rwanda should have already been on the Clinton administration’s agenda when it took office in January 1993.

When President Bill Clinton flew to Rwanda in 1998 (in a trip in which he never left the airfield), he claimed that he simply didn’t know what was happening in Rwanda. We now have further evidence that Clinton’s claims were false. It is not that the U.S. government didn’t know what was happening in Rwanda. The truth is that we didn’t care.

Timothy Longman is director of the African Studies Center and associate professor of political science and international relations at Boston University.