The U.S. government on May 21 informed its allies of intention to withdraw from the Treaty on Open Skies. The administration of President Donald Trump has long contemplated this move, citing Russian infractions and abuse of the treaty. The announcement came as separate leaks suggested that the Trump administration is considering a limited extension of New START, the treaty that governs the number of nuclear weapons Russia and the United States maintain. These actions add to the broader dismantling of the global arms control framework.

• The Treaty on Open Skies provides the United States and Russia, as well as its European signatories, with the ability to conduct observation flights over each other's territory as a means to achieve stability and trust by allowing mutual visibility of military facilities and deployments. Russia's refusal to allow these flights over certain Russian territories, as well as its increasing focus on the observation of civilian infrastructure during overflights of the United States, fueled opposition to the treaty.
• New START governs the number of nuclear weapons that both Russia and the United States field, but is set to expire in February 2021. While the treaty allows for a five-year extension upon both parties' agreement, the Trump administration has been reluctant to agree to this without expanding the scope of the treaty to include China.

The continued abandonment of arms control treaties is both an indicator and a driver of reduced trust and cooperation between the United States and Russia. Similar negative trends occurred during the Cold War, and were eventually followed by a revival of arms control efforts within that same bilateral context. One core problem that has plagued the viability of bilateral arms control treaties is the nonparticipation of China. Despite China's much smaller nuclear arsenal, its rise as a military power and technological advances in both strategic and conventional weapons have seen the reality of arms control evolve beyond the former Cold War bipolarity. In this more complex environment, sustaining legacy arms control measures becomes difficult, and establishing new ones is even further out of reach.

Under the Trump presidency and amid the context of increasing multipolar competition, the arms control framework that established limitations and guarantees between the United States and Russia during and following the Cold War has become progressively weakened. Last year, Trump withdrew from the INF Treaty, banning intermediate-range missiles from U.S. and Russian arsenals. The Trump administration didn't initiate this trend — former presidents George W. Bush withdrew from the Anti-Ballistic Missile Treaty in 2001 and Barack Obama considered abandoning the INF Treaty — it only happens to be occupying the White House as long-term questions on the sustainability of particular arms control treaties are coming to a head.