After the Holocaust, the world pledged "never again." But mass killings continued in Cambodia, Rwanda, the Balkans and -- most recently -- Sudan's Darfur region.
U.S. officials see a new risk of bloodshed in next month's independence vote in Southern Sudan. This time, everyone from celebrities to U.S. diplomats is trying a new approach: drawing attention to the risk of mass violence in hopes of preventing it.
Using unusually blunt language this fall, Secretary of State Hillary Clinton called the pending vote in Southern Sudan "a ticking time bomb of enormous consequence."
NBC's Dateline devoted an hour earlier this month to following George Clooney as he traveled across Southern Sudan, urging Americans to pay attention to the risk of violence. "I believe there is a real possibility of saving lives," Clooney said, "making it harder to kill people."
And Southern Sudanese themselves are trying to raise awareness. Hip-hop artist and former child soldier Emmanuel Jal released a song this month called "We Want Peace."
"I don't want my country to go back to war," Jal said in a phone interview from New York, where he was promoting the new song. "If the world knew 6 million Jews were going to die, they would have done something."
On Jan. 9, South Sudanese will go to the polls to vote on independence. After two decades of civil war with the North, most people in Southern Sudan seem to want their own country. A vote for secession would split Africa's largest nation in two.
But the North doesn't want to let the South go, and some fear it will use violence to stop it.
Jal's distrust comes from personal experience. Jal was one of Sudan's so-called Lost Boys, war orphans who suffered at the hands of Northern Army and its Arab militias. "When I was young, I've witnessed my home burned down, and my brothers and sisters were scattered for years," Jal said.
Jal worries next month he could see more of the same. He believes that the more people who pay attention to Southern Sudan, the safer people there will be. "What I always think is: A thief will not steal if the neighbors are screaming," Jal said.
No one in power screamed before the mass killings in Cambodia and Rwanda. Mike Abramowitz wants to change that.
Abramowitz runs the program on genocide prevention at the U.S. Holocaust Memorial Museum and spent two weeks in Southern Sudan this fall to evaluate and publicize the risks of violence. He says this new approach by activists and politicians is driven by past failures.
"The prevention of genocide really came up as a concept ... in the 1990s after Rwanda and after the Balkans," he said. "You started to have people in government -- Bill Clinton, for example -- who were very regretful of what happened on their watch."
But publicity alone has its limits.
Mohammed Hamad, who teaches political science at the University of Khartoum, says people in the Sudanese capital pay little attention to foreign activists, even stars like Clooney. "He's not well-known in Khartoum," Hamad says, adding that when it comes to activists like Clooney, Northern Sudanese "don't very much respect their views, actually."
But they do pay attention to the American government, which is pressing both sides to solve their deep differences short of war.
Samantha Power, the Obama administration's point person on human rights and preventing atrocities, says in the past, it often took a lot of bloodshed to get international attention. She says the U.S. responds quickly now to clashes, including recent bombings by the North of the Southern Sudan border.
"A single incident is enough for us to reach out and say, 'OK, tempers cool. If you retaliate, we know what's going to happen. It's going to be bad for your people as well as innocent people on the other side.' "
Power says diplomacy and awareness can do only so much.
Ultimately, she says, it's up to Sudanese leaders to make sure next month's vote is peaceful.