The world woke up to this phenomenon in 1993, after discovering that Serbian forces had set up a network of “rape camps” in which women and girls, some as young as 12, were enslaved. Since then, we’ve seen similar patterns of systematic rape in many countries, and it has become clear that mass rape is not just a byproduct of war but also sometimes a deliberate weapon.

“Rape in war has been going on since time immemorial,” said Stephen Lewis, a former Canadian ambassador who was the U.N.’s envoy for AIDS in Africa. “But it has taken a new twist as commanders have used it as a strategy of war.”

There are two reasons for this. First, mass rape is very effective militarily. From the viewpoint of a militia, getting into a firefight is risky, so it’s preferable to terrorize civilians sympathetic to a rival group and drive them away, depriving the rivals of support.

Second, mass rape attracts less international scrutiny than piles of bodies do, because the issue is indelicate and the victims are usually too ashamed to speak up.

In Sudan, the government has turned all of Darfur into a rape camp. The first person to alert me to this was a woman named Zahra Abdelkarim, who had been kidnapped, gang-raped, mutilated — slashed with a sword on her leg — and then left naked and bleeding to wander back to her Zaghawa tribe. In effect, she had become a message to her people: Flee, or else.

Since then, this practice of “marking” the Darfur rape victims has become widespread: typically, the women are scarred or branded, or occasionally have their ears cut off. This is often done by police officers or soldiers, in uniform, as part of a coordinated government policy.

When the governments of South Africa, China, Libya and Indonesia support Sudan’s positions in Darfur, do they really mean to adopt a pro-rape foreign policy?

The rape capital of the world is eastern Congo, where in some areas three-quarters of women have been raped. Sometimes the rapes are conducted with pointed sticks that leave the victims incontinent from internal injuries, and a former U.N. force commander there, Patrick Cammaert, says it is “more dangerous to be a woman than to be a soldier.”

The international community’s response so far? Approximately: “Not our problem.”

Yet such rapes also complicate post-conflict recovery, with sexual violence lingering even after peace has been restored. In Liberia, the civil war is over but rape is still epidemic — and half of all reported rapes involve girls younger than 14.

Painfully slowly, the United Nations and its member states seem to be recognizing the fact that systematic mass rape is at least as much an international outrage as, say, pirated DVDs. Yet China and Russia are resisting any new reporting mechanism for sexual violence, seeing such rapes as tragic but simply a criminal matter.

On the contrary, systematic rape has properly been found by international tribunals to constitute a crime against humanity, and it thrives in part because the world shrugs. The U.N. could do far more to provide health services to victims of mass rape and to insist that peacekeepers at least try to stop it.

In Congo, the doctors at Heal Africa Hospital and Panzi Hospital (healafrica .org and panzihospitalbukavu.org) repair the internal injuries of rape victims with skill and humanity. But my most indelible memory from my most recent visit, last year, came as I was interviewing a young woman who had been gang-raped.

I had taken her aside to protect her privacy, but a large group of women suddenly approached. I tried to shoo them away, and then the women explained that they had all been gang-raped and had decided that despite the stigma and risk of reprisal, they would all tell their stories.

So let’s hope that this week the world’s leaders and diplomats stop offering excuses for paralysis and begin emulating the courageous outspokenness of those Congolese women.