When Afghanistan ratified an international treaty this week banning the use of cluster munitions, it became the 62nd government worldwide legally committed to destroying stockpiles of the weapons and assisting those wounded by them.

But before the Kabul government decided to sign the treaty in late 2008, it was pressed against doing so by American officials, who feared that implementation could impede the ability of U.S. forces to use cluster munitions in Afghanistan, according to diplomatic cables released by WikiLeaks.

Cluster munitions, fired from air or land, are designed to explode into multiple bomblets before raining down on an enemy. But some of the bomblets don’t always explode — and when they land in areas populated by civilians, they are liable to later detonate much like landmines.

In Afghanistan, the Soviet Union used cluster munitions during the 1980s; Afghan forces deployed them during the civil war in the 1990s; and U.S.-led coalition forces used them against the Taliban in 2001 and 2002. There are 24 areas still contaminated by unexploded cluster bombs, mostly in residential and agricultural areas, and 40 people have been reported killed by them since 2001.

For years, those opposed to cluster munitions have campaigned for their elimination, citing the risks to civilians. And for years, the United States, which is not a signatory to the treaty, has argued that they are legitimate weapons when used properly. American military officials had pressed for the right to retain the munitions as part of their arsenal, including in Afghanistan, even if they were not commonly used.

The cables released by WikiLeaks underline American concerns that Afghanistan would approve the Convention on Cluster Munitions.

In 2008, before Afghanistan became a signatory to the treaty, then-American Ambassador William Wood met with Afghan President Hamid Karzai and National Security Adviser Zalmai Rassoul to discuss the issue. Rassoul, according to one cable, “said the Afghan government would not take any steps that would damage the U.S.-Afghan security relationship.”

Nonetheless, a short time later, the Afghan ambassador to Norway signed the treaty at a signing conference in Oslo, with Karzai’s permission. A cable from the State Department to the U.S. Embassy in Kabul details the “last-minute” change of policy, about which even some officials in Afghanistan’s Foreign Ministry were apparently unaware. It also says that U.S. government believed the treaty provided the military with the flexibility “to store, transfer, and use U.S. cluster munitions” in Afghanistan, an interpretation at odds with the reading of many experts on the issue.

American diplomats were urged to emphasize to officials in Kabul that a “narrow interpretation” of the treaty “will impair our ability to defend the lives of our soldiers as well as those of Afghanistan and Coalition partners.”

Afghanistan was among dozens of countries where U.S. diplomats attempted to minimize the impact of a growing global campaign to outlaw cluster bombs. A cable sent from London details a request from Britain, which is a signatory to the treaty, for the United States to remove American munitions from British territory, including the Diego Garcia military base, where some were stored. The cable says that top British officials had authorized temporary, case-by-case exceptions, an agreement intended to allow British lawmakers to say “that they have requested the [U.S. government] to remove its cluster munitions by 2013, without complicating/muddying the debate by having to indicate that this request is open to exceptions.”

In Norway, where talks on the convention began in 2007, a U.S. cable from 2008 described the country’s “less than helpful” response and “inflexibility” on the issue of cluster bombs. In Japan, which has since ratified the Convention on Cluster Munitions, cables record diplomatic attempts to discourage officials from doing so, and Japanese concerns that public pressure might force them to follow the British example of asking the U.S. military to remove cluster bombs from its territory.

“We know from WikiLeaks and from U.S. officials that during the negotiating process that the U.S. contacted more than 100 countries to talk to them about the convention,” said Steve Goose, who chairs the Cluster Munition Coalition, which has campaigned for a total ban on the weapons. “The U.S. contact ranged from expressing concern to twisting arms not to be part of the process and not to sign -- and they had a very concerted campaign to influence the language of the treaty.”

The State Department declined as a matter of policy to comment on the contents of the leaked cables, but spokeswoman Beth Gosselin said that the United States “shares the humanitarian concerns of those states that have signed and ratified the Convention on Cluster Munitions, as evidenced by our significant financial and technical support for conventional weapons destruction programs.” A spokesman for the US-led NATO mission in Afghanistan said that the force is not storing cluster munitions in Afghanistan.

Some defense experts say that cluster munitions are essential to effective fighting and that, without them, American troops would have to use even less discriminate weapons. Anthony Cordesman of the Center for Strategic and International Studies said that for American forces in Afghanistan, “if you have any organized attack on Afghan defenses, if you are talking about large Taliban formations, cluster munitions could be absolutely critical in stopping that.”

Cordesman added that the bombs have changed since the early models, which were prone to landing without exploding, saying that newer models deactivate if they do not explode on impact.

According to a 2008 policy memo by then-Defense Secretary Robert Gates, by 2018, all cluster munitions used by U.S. forces must operate to a standard whereby 99 percent of bomblets would detonate, limiting the amount of unexploded ordnance on the battlefield.

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