Jean Rostand, in his 1939 book Thoughts of a Biologist observed, “Kill one man, and you are a murderer. Kill millions of men, and you are a conqueror. Kill them all, and you are a god.”

History is replete with at least the conquerors. The Nazis killed six million Jews. Stalin’s forced famine killed up to 7.5 million Ukrainians. Pakistan’s Operation Searchlight killed three million in East Pakistan, now Bangladesh. Cambodian communists killed up to three million. Around two million African captives perished on slave ships during the Middle Passage. Another Stalin-imposed artificial famine killed up to 1.75 million Kazaks. Up to 1.5 million Armenians died at the hands of the Ottomans. A Roman general massacred one million Jews to quash a revolt in what is now Israel and Julius Caesar’s wars against the Gauls killed more than a million Celts.

In Rwanda, Hutus killed 500,000 mostly Tutsis and Pygmy Batwa in just 100 days.

Serbs killed 8,000 Muslim men and boys in Kosovo. Some 3,000 Chileans were killed or “disappeared” during Pinochet’s reign of terror. Atrocities in the Mid-east have killed hundreds of thousands and forced more than a million to flee to Europe.

And then there are the Houthis, the Yazidis and the Rohingya, all victims of religious ethnic cleansing.

The Houthis are locked in a civil war in Yemen and a coalition led by Saudi Arabia, a Sunni Muslim nation is bombing the desperately poor country, fearing a victory by the Houthis, who are Shi’ite Muslims, would be a boost to Shi’ite-dominated ran. The death toll so far is around 100,000. Both sides have been accused of atrocities but the coalition much more so, especially after two recent airstrikes killed 62 children. In one attack, the coalition dropped a bomb on a bus full of children on a school trip. United Nations human rights experts have accused the coalition of possible war crimes.

The Yazidis had the misfortune of not being Muslims at a time when an ascendant Islamic State of Syria and the Levant (ISIS) was on a killing spree in the region.

Lizzie Dearden reported in the U.K. Independent newspaper that 9,000 Yazidis fell victims in a matter of days and 3,100 of them were killed – half that number shot, beheaded or burned alive. Another 6,800 were kidnapped, mostly women and children. The stories being told by women forced into sexual slavery are among the most heart-breaking in modern times.

ISIS’ religious leaders issued edicts to justify the women’s sexual enslavement, including regulations on how to treat them. Emma Graham-Harrison wrote in the Guardian that ISIS “set up markets in several towns where girls as young as 9 were put up for auction to militants, with owners often trading women again online.” Noor, a former enslaved woman, said, “I was sold seven times — and lots of women had a much worse life than me.”

The Rohingya have been targeted by a Myanmar military campaign so destructive that the United Nations has called for the prosecution of the commander-inchief and five generals as war criminals.

They number around one million Muslims in a country of 59 million mostly Buddhists. Intermittent clashes between small, armed groups of Rohingya, who have been demanding autonomy, and the entirely one-sided conflict exploded in the current sustained military campaign. Soldiers have rampaged through their home state Rakhine, killing, raping and burning villages.

Myanmar insists that the Rohingya have been living illegally in the country, deems them Bengalis from nearby Bangladesh and denies them citizenship but they claim a presence in the country going back a millennium. Some 900,000 have fled to Bangladesh, where they live in appalling conditions in refugee camps.

The U.N. released a report on the first anniversary of the military crackdown from a fact-finding mission. The leader, Marzuki Darusman, said investigators interviewed 875 witnesses and victims and examined satellite imagery and verified photos and videos. The testimony they heard point to atrocities that are “among the most shocking human rights violations” he had ever witnessed, Al Jazeera reported him as saying. Secretary of State Mike Pompeo declared in Geneva, “The U.S. will continue to hold those responsible accountable.” Nikki Haley, ambassador to the United Nations, told the Security Council that “the world can no longer avoid the difficult truth of what happened.”

But words are not enough, especially when they come too late. As the world’s leader, we are called to a higher purpose than just being engrossed in domestic politics. We have the political, economic and military leverage to intervene decisively when vulnerable peoples are victimized. We have done it on occasion but, when we do not, we, too are complicit.