Last week, Japanese Prime Minister Shinzo Abe asserted that there is “no proof” that women were forced into sexual bondage to serve the Japanese military during World War II, in effect labeling as prostitutes or liars all the thousands of victims of this abhorrent practice. After international outrage erupted, Abe stepped back, but by then the survivors had once more been victimized by his denial of an overwhelming historical record.

The prime minister’s revisionist statement contradicts abundant evidence that has come to light despite the government’s efforts to conceal or minimize the mistreatment of thousands of women in about 2,000 wartime brothels run by or with the cooperation of the Japanese military. Most historians estimate the number of girls and women conscripted to provide sex to Japanese soldiers at between 100,000 and 200,000. Most were Korean and Chinese, though they also included other Asians and Europeans from Japanese-occupied areas. Many were kidnapped and raped, others were tricked or defrauded; some were sold by their families.

Japanese soldiers have come forward during the last 15 years to admit to forcibly taking girls and women on orders of the military. In 1992, documents found in the archives of Japan’s Defense Ministry indicated that the military was directly involved in running the brothels. The Japanese government formally apologized to the women in 1993. Since then, Japan’s official position has been one of admitting moral but not legal responsibility. A private fund was set up to compensate the former “comfort women,” and two Japanese prime ministers wrote formal letters of apology to women who received the payments. Some victims claimed that this ambiguity was unacceptable and refused to accept compensation.

The Japanese government claims that even if the women were held involuntarily, there was no law against it at the time; alternatively, if coerced sexual relations were illegal, the laws did not apply in militarily-occupied territories. A third prong of the Japanese defense is that any misconduct that did occur was settled by the peace treaties at the end of the war. Human rights activists in Japan and abroad have sought to prove this wrong, but so far they have been unable to secure redress for “comfort women” who have come forward in recent years.

In 2000, the Tokyo District Court dismissed a case brought by 46 former sex slaves from the Philippines who accused Japan of war crimes and crimes against humanity. The court wrongly decided that “crimes against humanity” were not part of international law at the time. In 2001, a reparations claim by South Korean women who had been held as sex slaves failed in the Hiroshima High Court on the similarly erroneous grounds that coerced sex wasn’t illegal at the time.

However, there is a strong case to be made that the Japanese government does owe the women damages. Rape and kidnapping were crimes in Japanese law at the time and should have led to prosecutions of soldiers committing them. Moreover, despite the ruling in Tokyo District Court, the notion of crimes against humanity goes back to 1904, and such crimes were indicted after World War I and successfully prosecuted after World War II. On top of that, Japan had joined in four international treaties that barred sexual trafficking in women and forced labor. In 1999, the Federation of Korean Trade Unions invoked these treaties and requested the International Labor Organization to rule that the women held by Japan in official brothels constituted forced laborers. The ILO Committee of Experts upheld the claim, but the ILO had no power to order relief.

The victims also run into problems with the peace treaties that ended World War II. For example, the 1951 US-Japan peace treaty “recognized that the resources of Japan are not presently sufficient, if it is to maintain a viable economy, to make complete reparation” for damage and suffering. Japan has argued that this provision and others in peace treaties with some of its Asian neighbors and European powers closed the door on reparations claims by former prisoners of war, “comfort women” and other victims of Japanese atrocities and that nothing is owed anyone today.

However, several provisions in the peace treaties suggest that reopening the issue of reparations might be possible, and advocates should look carefully at the texts. Still, it seems no court is likely to cure the injustice; Japan has a moral and legal obligation to do so.

Dinah L. Shelton is a professor of law at George Washington University.