The American relationship with Recep Tayyip Erdoğan’s Turkey has been fraught for half a decade, but never this bad. Last week, American troops were intentionally targeted by Turkish artillery units in Northern Syria as Erdoğan’s forces advanced and President Donald Trump ordered the U.S. into a unilateral withdrawal. The Pentagon sternly warned that Turkey’s troops would face “immediate defensive action” from American forces if such an encounter were to be repeated.

This was a doubly unprecedented targeting of the United States military. As a member of the North Atlantic Treaty Organization, Turkey is a capital-A ally, treaty-bound to defend the collective security of all its 28 nation members, including the United States. Turkey is also part of a select group of five NATO members—along with Belgium, the Netherlands, Germany, and Italy—whose territory hosts American nuclear weapons, too.

During the Cuban Missile Crisis, newly established U.S. nuclear missile batteries in Turkey were briefly famous, becoming a bargaining chip in the negotiations to avoid atomic war with the Soviet Union. Those missiles were removed in 1963, but 50 B61 nuclear gravity bombs currently reside in specialized underground vaults at Incirlik Air Base in southern Turkey, some 20 miles from the Mediterranean coast. These air-dropped bombs are capable of delivering a range of nuclear yields, from 300 tons up to 170 kilotons, or roughly eleven times the yield of the bomb the U.S. dropped on Hiroshima in August 1945. (For a more concrete description of these weapons’ destructive force, watch this.) Turkish F-16 fighters used to be certified to carry and deliver these weapons, but Turkey no longer has the pilots for that task; now, the weapons at Incirlik are there for rotational U.S. aircraft to drop them, if it’s ever necessary.

In light of Turkey’s precipitous Syrian advance, it’s fair to ask whether the U.S. should reconsider its weapons posture at Incirlik—or, as arms-control researcher Jeffrey Lewis put it last week: “Seriously, it’s time to take our fucking nuclear weapons out of Turkey.” That thought apparently also occurred to U.S. officials at the State Department and Department of Energy; sources tell The New York Times that since Erdoğan’s onslaught against the Kurds began, those officials have been “reviewing plans” to get the bombs out of Incirlik. It should have happened much sooner—say, when a coup threatened to topple Erdoğan’s government in 2016, or in the aftermath, as he drifted from the U.S.’s orbit—but removing a nuclear arsenal from Turkish soil is a necessary step in reducing a global danger. Alliances are built on closely shared interests and values, and—presidential phone calls notwithstanding—the U.S. and Turkey no longer have any.

Technically, we didn’t know that those 50 or so warheads were still at Incirlik until the Times report confirmed it this week. It’s general American policy to neither confirm nor deny the specific location of nuclear weapons on vessels and storage sites overseas. That practice was a major part of what led to the late-1980s rupture in the U.S.-New Zealand alliance: Wellington’s Labour government grew uncomfortable with the likelihood of nuclear weapons passing through New Zealand waters, and the U.S. government wouldn’t certify that its vessels were explicitly nonnuclear.