The bloody genocides in Rwanda and the Balkans during the 1990s continue to cast long shadows: In April, the entire Dutch government resigned for its role in failing to prevent the 1995 capture of Srebrenica by murderous Bosnian Serb forces. Former Yugoslav President Slobodan Milosevic is on trial in The Hague for war crimes his regime committed in Bosnia, Croatia, and Kosovo. In A Problem From Hell: America and the Age of Genocide, journalist Samantha Power offers a superb analysis of U.S. policy toward genocides since the Holocaust. She has amassed a vast and impressive collection of documents that lead to an awful conclusion: "No U.S. president has ever made genocide prevention a priority, and no U.S. president has ever suffered politically for his indifference to its occurrence. It is thus no coincidence that genocide rages on."

U.S. lawmakers and other government officials have repeatedly and somberly invoked the Holocaust and said "never again," but what has the government actually done when faced with modern-day genocide? Pathetically little, Power shows.

When the Khmer Rouge starved and bludgeoned nearly 2 million Cambodians to death from 1975 to 1979, Washington did not have the stomach to take on a regime that bordered Vietnam. The innocent Cambodian people had the misfortune of being in the same neighborhood as the victor that had just chased out the United States, which was still smarting from its war wounds.

When Iraq unleashed chemical weapons on the Kurdish town of Halabja in 1988, immediately killing 5,000 of its own citizens, Washington was skeptical because reports of the incident came from Iran, its enemy. Washington was also determined to maintain the status quo with Iraq on trade and access to oil.

The irony of what Power calls "the g-word" is that the term's grim meaning makes the United States and other nations overly cautious in invoking it. They are often reluctant to use it at all. They know that the word creates a moral imperative to take action, so they avoid labeling any situation a genocide. "Be careful ... Genocide finding could commit [the U.S. government] to actually 'do something,' " warned a 1994 paper on Rwanda. An official in the Defense secretary's office prepared the paper less than a month into the country's 100-day genocide. Susan Rice, who at the time was a member of the National Security Council staff, reportedly asked during an interagency teleconference late in the month when the genocide began: "If we use the word 'genocide' and are seen as doing nothing, what will be the effect on the November [congressional] election?"

The State Department referred to "acts of genocide" in Rwanda rather than declaring outright that all-out genocide was occurring. On Bosnia, the department waited until the very last day of George H.W. Bush's presidency in 1993 to declare that the violence "probably borders on genocide." That timid declaration came nine months after the atrocities began.

The title of Power's book is taken from a 1993 remark by then-Secretary of State Warren Christopher, who said in an interview about warring Muslim, Croat, and Serb communities in Bosnia: "The hatred between all three groups ... is almost unbelievable. It's almost terrifying, and it's centuries old. That really is a problem from hell. And I think that the United States is doing all we can to try to deal with that problem." But, as Power argues, the United States was not doing anywhere near all it could to stop bloodshed in the disintegrating country. Power, who was a war correspondent in Bosnia for The Washington Post before becoming a professor of human rights and U.S. foreign policy at Harvard University, admits she is haunted by her own failure to sound a proper alarm about Srebrenica.

Power's story has a few heroes: former Sen. William Proxmire, D-Wis.; Raphael Lemkin, a Polish Jew who coined the word "genocide" in 1944; and Peter Galbraith, who worked for the Senate Foreign Relations Committee before becoming ambassador to Croatia in 1993. Lemkin and Galbraith, sadly, were generally not admired for their efforts to combat genocide. Proxmire gave 3,211 speeches between 1967 and 1986 urging ratification of the 1948 Convention on the Prevention and Punishment of the Crime of Genocide. (In 1986, 38 years after the convention was approved by the United Nations, the United States finally ratified the treaty. Ninety-seven other countries had already accepted it.) Other heroes are the generally unknown State Department experts who study individual nations. Most of them are sincerely concerned about the countries they focus on and are less motivated by politics.

The most tragic hero is Romeo Dallaire, a stalwart Canadian major general who carries the devastating burden of having headed the U.N. peacekeeping mission in Rwanda when the country was plunged into genocide. Less than three weeks after the killings started, his troops were reduced from 2,500 to 503 after 10 Belgian peacekeepers were killed. Belgium withdrew its 400-plus peacekeepers, and the U.N. Security Council voted to slash the mission's troop strength.

Our society can learn from its tragic tendency to avoid facing up to the mass slaughter of humans in foreign lands. But like Dallaire, who is haunted by the eyes and spirits of the victims he saw, we have to live with the fact that at least 800,000 Rwandans were murdered on our watch. "We have all been bystanders to genocide," Power laments.

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