On Monday, the Trump administration announced the United States would be withdrawing from the Treaty on Open Skies, an agreement between 34 nations that allows unarmed military aircraft to fly over each other's territory for observation purposes.
One of the key benefits to the treaty is that it allows the United States and its allies to fly over Russian airspace for the purpose of gathering intelligence — 42 overflights of Russian territory per year are permitted under the treaty, including 16 overflights by the United States specifically. These flyovers were important to monitoring Russia as they invaded and occupied the Crimean Peninsula.
But Trump has soured on the treaty in recent months, claiming that Russia is not in "complete compliance with [its] obligations." In August 2018, the Trump administration moved to block funding for the treaty in the annual defense authorization bill, and two months later, Trump officials refused to certify a Russian airplane for Open Skies overflights, alone among the treaty's signatories — but quickly changed course and approved the flight.
Russia, for its part, has accused the United States of being in violation of the treaty, with Federation Council Foreign Affairs Minister Vladimir Dzhabarov saying of the original defunding effort, "This is an attempt to hide everything the Americans will be preparing in the course of a new arms race."
"NATO allies and partners, and Ukraine in particular, have repeatedly stressed the importance of the Open Skies Treaty for their efforts to monitor Russia's military, wrote House Foreign Affairs Committee Chairman Eliot Engel (D-NY) in a letter to National Security Adviser Robert O'Brien. "Withdrawal risks dividing the transatlantic alliance and would further undermine America's reliability as a stable and predictable partner when it comes to European security."
Naval War College professor Tom Nichols, a Trump-skeptic conservative and military expert, had an even blunter reaction: "There is literally no reason to do this, other than to tell Rube Nation 'I pulled out of treaties.'"