A simmering diplomatic incident between Ankara and Washington has developed over the use of surveillance information provided by a U.S. Predator drone. In late December 2011, the drone spotted a caravan of 38 men and pack mules on a mountain ridge in the Kurdish region of Turkey near the border with Iraq. U.S. military personnel operating the drone suspected that the caravan consisted of fighters for the insurgent Kurdistan Workers Party (PKK) and relayed the information to Turkey’s military command. A short time later, Turkish aircraft attacked the caravan, killing all but four of the men. The incident sparked several riots in towns throughout Turkey’s Kurdish region.

It also caused growing uneasiness at the Pentagon and in Congress. Pentagon officials were quick to insist the United States bore no real responsibility for the attack. They conceded that the drone supplied information about the caravan, but “the Turks made the call,” a senior U.S. Defense Department official emphasized. “It wasn’t an American decision.”

Critics greeted that explanation with some skepticism. The principal concern was whether those killed had really been PKK guerrillas, as Ankara insisted, or whether the men had been garden-variety gasoline smugglers, as most of the evidence indicated. If they had that status, they clearly did not deserve to be slaughtered by Turkish military aircraft. And that possibility highlighted a related concern—whether Ankara had misused sophisticated U.S. military hardware. Worried members of the American foreign policy community asked how far Washington should entrust allies, even a fellow NATO member like Turkey, with deadly drone technology.

It is not the first time that questions have arisen about how a U.S. security partner has utilized American weaponry or intelligence data. There have been numerous calls over the decades to cut-off aid to Pakistan’s military because of acts of aggression those forces have taken against India and coups they have launched against Pakistan’s own civilian government. In the early 1980s, angry members of Congress, as well as human rights activists, called on the White House to curtail military aid to South Korea when the South Korean army overthrew an embryonic democratic government. Critics inside the United States and throughout the Muslim world have repeatedly demanded (to no avail) that U.S. military aid to Israel be restricted because Tel Aviv has used helicopters and other systems to attack Palestinian demonstrators.

Turkey itself has been the target of complaints about improper use of American aid. The most prominent anti-aid campaign occurred after Turkish forces invaded Cyprus in 1974 and occupied nearly 38 percent of that country’s territory. Congress did cut-off military aid to Ankara, although the executive branch managed to restore most of assistance gradually over the next few years. Ankara’s use of U.S.-supplied attack helicopters against Kurdish targets inside Turkey—and even more so beginning in 2008 when those weapon systems were used against accused PKK sanctuaries in northern Iraq—led to renewed calls for severing aid. As in the case of Pakistan, it appeared that U.S. weaponry was, despite supposed prohibitions, being employed to commit aggressive acts against a neighboring country.

The latest incident involving drone intelligence enabling the Turkish military to attack an apparent caravan of smugglers has intensified all of those concerns. U.S. aid, even indirect aid, to such a deadly attack highlights Washington’s moral entanglement in questionable actions that allies such as Turkey undertake. There is also the considerable risk that angry populations who have been the targets of such attacks will hold the United States responsible for any unjustified casualties.

That danger was highlighted during the successful anti-government demonstrations against Hosni Mubarak’s government in Egypt. Demonstrators were noticeably angry at the sight of U.S.-provided helicopters and armored vehicles being used against unarmed civilians who sought to bring democracy to their country. Such anger can lead to the growth of already worrisome anti-American sentiment in the Middle East and other regions. U.S. leaders need to take into account that potential cost the next time they help arm allied governments that have questionable agendas.

Ted Galen Carpenter, a senior fellow at the Cato Institute, is the author of eight books on international affairs and is a member of the editorial board of Mediterranean Quarterly.