The United Nations may not have much to fear from the lawsuit filed this week by relatives of those killed or sickened in Haiti’s cholera epidemic. The UN and its representatives, after all, enjoy almost total immunity from legal claims.

Even if it prevails in U.S. federal court, however, the UN’s reputation and credibility will suffer if it continues to dodge responsibility for an outbreak that so far has killed an estimated 8,200 people and sickened 669,000.

UN officials say the cause of Haiti’s epidemic is unclear. It’s a bogus claim. Before the outbreak, cholera was last seen on the island of Hispaniola in 1867. Then, in October 2010, to help Haiti recover from a powerful earthquake earlier that year, UN peacekeepers arrived in the town of Meye from Nepal, where cholera is endemic. Their base’s haphazard sanitation system leaked sewage into a nearby tributary to the Artibonite River, a major source of drinking water. Within days, hospitals registered cholera cases traced to the tributary. The bacterium responsible for Haiti’s epidemic proved to be of Nepalese origin.

It’s true, as the UN points out, that the dearth of clean water and good sanitation in Haiti facilitated the spread of the disease. But these vulnerabilities do not absolve the UN of its responsibility to protect the population from just this sort of pathogenic assault.

That it did not was negligent. UN officials neither tested the peacekeepers from Nepal for cholera, despite an outbreak there just before their deployment, nor ensured that their sewage system was sound, violating a basic principle of aid organizations that, at the very least, they should do no harm.

By refusing to even hear claims from Haitians affected by the epidemic, the UN is violating not only the norms of decency but also its own rules. Yes, a 1946 treaty grants the UN immunity from “legal process”; its representatives are granted the same for acts committed while discharging their duties. Yet the convention also mandates that the UN establish mechanisms to settle disputes to which it is a party.

When it comes to the behavior of UN peacekeepers, that mechanism -- according to agreements the UN has signed with 32 host countries, including Haiti -- is supposed to be a three-member standing commission, with one member named by the government, one by the UN secretary-general and one appointed jointly. In Haiti -- as well as in those 31 other countries -- the UN has failed to create such a commission.

Thus, those affected by Haiti’s cholera debacle had no choice but to take their case initially to the UN itself. More than 5,000 victims of the epidemic filed a petition with the UN a year ago seeking compensation and an apology. The secretary-general’s office replied that the complaint was “not receivable” because it would require “a review of political and policy matters.”

If the complaint did require such a review, all the better. But that’s not the purpose of the suit. The 1946 treaty promises recourse for disputes of a “private law character,” which includes claims of compensation for personal injury or death. The UN should accept responsibility for the epidemic, apologize, and create a compensation fund for families of the dead, the ailing and the many more who are expected to fall victim to cholera in Haiti over the next decade. It should also aggressively pursue the estimated $2 billion still needed to improve Hispaniola’s water and sanitation system over the next 10 years.

As far as the lawsuit is concerned, the odds are with the UN. But in its obstinacy, the UN hampers its ability to promote accountability, fairness, the rule of law and the amicable settlement of disputes. Not to mention good hygiene.

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