“Our government has failed to denounce the suppression of democracy. Our government has failed to denounce atrocities… Our government has evidenced what many will consider moral bankruptcy.” – Archer Blood, American diplomat, April 6, 1971.

Blood wrote this dispatch two weeks into the bloody massacre that would lead to the birth of Bangladesh. Unlike the Rwandan genocide, or the Holocaust, or the killing that followed the breakup of Yugoslavia, the genocide in Bangladesh that ended 45 years ago this week has largely slipped out of public awareness—even though the upper estimate for the death toll is 3 million. With the ongoing debate over how or even if America should assist Syria and those trapped in Aleppo, understanding how the U.S. has responded to genocides in the past is more crucial than ever.

In 1947, the partition of British India split the subcontinent into the independent nations of India and Pakistan, each a home for their respective religious majorities, the Hindus and the Muslims. But the unwieldy logistics of this divide meant Pakistan included two chunks of land separated by more than 1,000 miles of Indian territory.

The geographic distance between West and East Pakistan was mirrored by their economic and political separation. With most of the ruling elite having immigrated westward from India, West Pakistan was chosen as the nation’s political center. Between 1947 and 1970, East Pakistan (which would eventually become Bangladesh) received only 25 percent of the country’s industrial investments and 30 percent of its imports, despite producing 59 percent of the country’s exports. West Pakistani elites saw their eastern countrymen as culturally and ethnically inferior, and an attempt to make Urdu the national language (less than 10 percent of the population in East Pakistan had a working knowledge of Urdu) was seen as further proof that East Pakistan's interests would be ignored by the government. Making matters worse, the powerful Bhola Cyclone hit East Bangladesh in November of 1970, killing 300,000 people. Despite having more resources at their disposal, West Pakistan offered a sluggish response to the disaster.

As French journalist Paul Dreyfus said of the situation, “Over the years, West Pakistan behaved like a poorly raised, egotistical guest, devouring the best dishes and leaving nothing but scraps and leftovers for East Pakistan.”

In 1970, West Pakistan announced the country would hold an election for its first general elections since the country gained independence. Like other Pakistani leaders before him, West Pakistan’s chief martial law administrator and president, General Agha Mohammad Yahya Khan, placed limits on the freedoms of voters, indicating that the integrity of the country of Pakistan was more important than the election outcomes. This practice of “Basic Democracy” had been used in the past to provide the appearance of democracy while still leaving the military in true control.

In this election, 138 seats would go to West Pakistan representatives and 162 to the more populous East Pakistan (which had about 20 million more inhabitants). While West Pakistan’s votes were split between different parties, an overwhelming majority of votes in East Pakistan went to the Awami League led by Sheikh Mujibur Rahman, who campaigned on a platform of Bengali autonomy.

Shocked by the results and what they meant for the stability of the country, Yahya Khan delayed calling the first meeting of the assembly and instituted martial law. Riots and strikes erupted across East Pakistan, with Mujibur announcing the start of a civil disobedience movement in front of a crowd of 50,000 on March 7, 1971. A last ditch effort to avert war occurred in Dhaka, the capital of East Pakistan, from March 16 to 24. Mujibur and Khan met, discussed the issues, and seemingly reached an agreement—but on the night of March 25, Mujibur was arrested and 60-80,000 West Pakistani soldiers, who had been infiltrating East Pakistan for several months, began what would be known as Operation Searchlight, the massacre of Bengali civilians by Pakistani soldiers.

Estimates for the total number of deaths range from 500,000 to over 3 million, with the death toll having become politicized over the years, says Lisa Curtis, a senior research fellow at the Heritage Foundation’s Asian Studies Center.

“Regardless of what the number is, clearly massive atrocities took place against the Bengali people,” Curtis says. “I think we have to say that the atrocities committed by the Pakistan military far outstripped what we saw from the other side.”

The '3 million' figure came from the Soviet newspaper, Pravda, reported investigative journalist David Bergman in a New York Times op-ed, and it has been used to create a national narrative about Bangladesh and its formation that allows the government to extend its judicial power.

By halfway through the nine-month genocide, the U.S Central Intelligence Agency gave a conservative estimate of 200,000 Bangladeshis murdered. There was violence on all sides, with some fighting between Bengali factions (whose goals for independence or unity with West Pakistan differed), but it seems clear that Pakistani soldiers perpetrated most of the brutal attacks, many wielding weapons supplied by the U.S., since Pakistan was considered an American ally. In May 1971, 1.5 million refugees sought asylum in India; by November 1971 that number had risen to nearly 10 million. When Australian doctor Geoffrey Davis was brought to Dhaka by the United Nations to assist with late-term abortions of raped women, at the end of the war, he believed the estimated figure for the number of Bengali women who were raped—200,000 to 400,000—was probably too low.

All the while, tensions were gradually increasing between Pakistan and India, with both sides calling in reserve troops to prepare for a possible conflict along the Pakistan-Indian border. The massacre in Bangladesh came to an abrupt end when West Pakistan declared war on India in early December. By December 16, India forced Pakistan into unconditional surrender, and 90,000 Pakistani soldiers became prisoners of war. Bangladesh had achieved its independence—but at an incredibly high cost.

The world at large was well aware of the violence happening in Bangladesh throughout Operation Searchlight. Indian Prime Minister Indira Gandhi termed the attack “genocide” as early as March 31 of that year. Blood, the American consul-general in Dhaka, and Kenneth Keating, the U.S. ambassador to India, both called on President Nixon to discontinue their support of the Pakistani regime. Both diplomats were ignored and Blood was recalled.

Overshadowing the genocide were the ongoing tensions of the Cold War. Nixon and his national security advisor, Henry Kissinger, considered Pakistan a close ally in the region. The U.S. provided weapons, and used Pakistan as a gateway to open diplomatic relations with China.

Further complicating matters was India’s closeness with the Soviet Union. In August 1971 the two countries signed the “Treaty of Peace, Friendship and Cooperation” that seemed to indicate India would be relinquishing its role as a neutral bystander in the Cold War. Nixon and Kissinger were both terrified about the possibility of India intensifying their relationship with the U.S.S.R. and not overly concerned about Pakistan’s military action in Bangladesh—or the reaction of Americans who read about it.

“Biafra [another genocidal war in Nigeria] stirred up a few Catholics,” Nixon was recorded saying. “But you know, I think Biafra stirred people up more than Pakistan, because Pakistan, they’re just a bunch of brown goddamn Muslims.”

As political scientist Gary J. Bass writes, “Above all, Bangladesh’s experience shows the primacy of international security over justice.”

Despite gaining their independence, Bangladesh has struggled to overcome its bloody history. Although the current prime minister of Bangladesh, Sheikh Hasina, has instituted an International War Crimes Tribunal, the process has specifically targeted Hasina’s political opposition, says the Heritage Foundation’s Lisa Curtis.

In addition to highlighting how one country has struggled to come to terms with its past, Curtis says the Bangladesh genocide should be further studied to help understand how the U.S. deals with massive atrocities happening abroad.

“How do we look at these from both a U.S. values perspective, but also a national interests perspective?” Curtis says. “And where do those values and national interests combine to merit a stronger response?”

The answer to that question, it often seems, is only clear in retrospect, when no more action can be taken.

Editor's note, December 22, 2016: This article originally misstated the date of Sheikh Mujibur Rahman's rally calling for civil disobedience. It was March 7, 1971, not March 4. The error has been fixed.