The Obama administration’s weapon of choice is the drone, which has a largely undeserved reputation as one of the more precise weapon platforms ever created. The result has been that much of the discussion of Obama’s foreign policy has revolved around the ethical and legal implications of assassination (and failed assassination) by remote control. But, as President Barack Obama’s second term draws to a close, one element of his foreign policy legacy has gone almost entirely unremarked upon: the United State’s continued manufacture and export of cluster munitions.

Unlike drones, cluster bombs are impossible to justify as targeted or as a reasonable way to minimize civilian casualties. By their very nature, cluster bombs, which essentially become landmines if they don’t blow up in mid-air, are “dumb” weapons that can linger for decades if unexploded. Though the U.S. government does not generally use cluster bombs itself, U.S. companies continue to manufacture cluster bombs that the government allows to be exported to allies — allies like Saudi Arabia.

“Cluster munitions are dropped from aircraft or fired from the ground or sea, opening up in mid-air to release tens or hundreds of submunitions, which can saturate an area up to the size of several football fields,” reads the Cluster Munition Coalition’s explanation of its explosive enemy. “Anybody within the strike area of the cluster munition, be they military or civilian, is very likely to be killed or seriously injured.”

Currently, 119 nations are members of the Convention on Cluster Munitions, though the U.S. is not. Neither is Saudi Arabia. Beginning in March 2015, the latter country began an open-ended bombing campaign against Yemen, and one of their weapons of choice is U.S.-made cluster bombs. Textron, a U.S. manufacturer of cluster bombs, got a stock upgrade shortly after the Saudi-led bombing began.

Though the Saudi-led coalition’s war is rarely covered in the U.S. media, the United States plays several crucial roles in the campaign. For one, the U.S. is providing Saudi Arabia with intelligence for targeting decisions, and logistics help, like in-flight refueling. For another, the Obama administration has sold the Saudis nearly $50 billion in weapons deals, including $640 million in cluster munitions.

One notable U.S. attack that did include cluster bombs was a 2009 U.S. airstrike on the village of al-Majala, in Yemen. The strike killed 41 civilians, including 22 children. An Amnesty International investigation the following year found fragments of a U.S.-manufactured cruise missile, which contained cluster submunitions, at the impact site. Though the U.S. denied it carried out the strike, subsequent Wikileaks cables confirmed the U.S.’s role.

It’s not just Saudi Arabia who is using cluster munitions, either. Human Rights Watch reported in February that Russian and Syrian forces were using cluster bombs against civilians in rebel-held areas. Just this year, between January 26 and February 8, joint Russian-Syrian forces used cluster munitions at least 14 times, killing at least 37 civilians. Included in the dead were six women and nine children.

“Any solution of the Syrian crisis needs to address ongoing indiscriminate attacks,” said Nadim Houry, deputy Middle East director, in a statement. “A good place to start would be a commitment by Russia and Syria to stop using cluster munitions.”

It is impossible to defend the U.S.’s decision to continue to manufacture and export cluster bombs, despite promises from manufacturers that only a small fraction will be “duds.” Americans are rightly horrified to learn of indiscriminate Russian attacks on civilians, or of Assad’s use of chemical weapons — yet cluster munitions continue to be one of the deadliest and most indiscriminate weapons used in war worldwide.

The U.S. government would be wise to prohibit the creation and sale of cluster bombs, and to join both the Convention on Cluster Munitions and the Landmine Ban Treaty. As it stands now, the Obama administration’s willingness to allow the Saudi coalition to deploy U.S.-made cluster bombs is a low point in his legacy.