Over the last 48 hours, national news outlets have begun reporting that Ukrainian militias used U.S.-made armored vehicles (albeit unconfirmed by the U.S. government) in an attack over the Russian border and that Ukraine’s security services conducted a drone attack against the Kremlin earlier this month. It is important to note that despite Washington’s support for Ukraine, the United States was not involved in either attack. This recent escalation – with U.S. weapons systems in one case – is disappointing but not surprising.

Since the start of the conflict, I have written eight different editorials addressing loose weapons in Ukraine. This weapons dispersion happens for a few reasons. First, there is a history of weapons dispersion in Ukraine. According to the 2021 Global Organized Crime Index, Ukraine has one of the largest illegally trafficked arms markets in Europe, especially when it comes to small arms and ammunition. About 300,000 small arms and light weapons were reported lost or stolen after Russia seized land during the invasion of Crimea between 2013 and 2015. Of these, only slightly more than 13 percent are recovered, while the vast majority remains in circulation on the black market.

All of this was already a problem before the conflict. The invasion exacerbated these issues as the country was flooded with a sudden influx of millions of arms and ammunition and an increasing number of civilians received military training and weapons. As Rep. Sara Jacobs (D‑CA) noted at a 2022 Cato policy forum on the risk of weapons trafficking in Ukraine, the United States does not “have the capacity to do the end‐​use monitoring we were doing before” because monitoring changes when you begin to “arm an insurgency.”

This sort of weapons dispersion is not surprising, nor are its effects. Loose U.S. weapons threaten to entangle the United States in a conflict with another nuclear power by unintentionally increasing escalation against Russia, while also risking further destabilization within Ukraine if a disagreement breaks out between different armed groups or in any post-conflict situation.

The world has seen weapons dispersion of U.S. arms cause similar damage twice over the last two years. First, in Afghanistan, where the Taliban have used U.S. weapons left behind to arm themselves and generate profits. Second, in Yemen, when U.S. weapons sales to Saudi Arabia turned the United States into an unwitting participant in the conflict.

Nonetheless, while the damage done in Afghanistan and Yemen is severe, they pale in comparison to what could happen in Ukraine. Dispersion in Ukraine risks great power war and destabilization in Eastern Europe. Regrettably, there is little that the United States can do now to prevent this from continuing to happen.