BOSTON

On Thursday, the United Nations secretary general, Ban Ki-moon, rejected a legal claim for compensation filed in 2011 on behalf of cholera victims in Haiti. Through a spokesperson, Mr. Ban said the claims, brought by a nongovernmental organization, were “not receivable” because of the United Nations’ diplomatic immunity.

Regardless of the merits of this argument, the United Nations has a moral, if not legal, obligation to help solve a crisis it inadvertently helped start. The evidence shows that the United Nations was largely, though not wholly, responsible for an outbreak of cholera that has subsequently killed some 8,000 Haitians and sickened 646,000 more since October 2010. The United Nations has not acknowledged its culpability.

Now, as the cholera epidemic appears to worsen, Mr. Ban and the United Nations have an opportunity to save thousands of lives, restore good will — and, yes, fulfill the mandate that brought the organization to Haiti in the first place: stabilizing a fragile country. The United Nations should immediately increase its financial support for the Haitian government’s efforts to control the epidemic. While that may not satisfy everyone, it will go at least some way toward compensating the people of Haiti for the unintentional introduction of the bacteria that caused the epidemic.

Before October 2010, cholera — a diarrheal illness caused by consuming water or food contaminated with the bacterium Vibrio cholerae — had never been reported in the country. In the epidemic’s first year, the striking loss of life attracted international media attention. Even in its third year, the outbreak continues to sicken thousands.