The Kremlin says that without Washington, there's little reason to continue Russian participation, despite the more than two dozen other participating nations. "We respect the decision of the participating States remaining in the Treaty to continue its implementation. We wish them constructive and fruitful collaboration," a formal statement reads. "However, it is obvious that without the participation of the United States and our country, the effectiveness of the Treaty on Open Skies will decrease sharply: the area of application will drop by about 80 percent, and the number of Open Skies missions planned for 2022 will severely decrease," the ministry said.

Initiated in 1992 and then ratified in 2002, it allowed the 35 member states that eventually joined it to conduct short-notice, unarmed observation flights to monitor other countries' military operations in mutual verification of arms-control agreements. Russia says that nearly 450 reconnaissance flights were allowed over its territory since the treaty was initiated three decades ago.

The treaty even allowed Russian recon flights over tightly restricted Washington D.C. airspace — in past years Russian Tupolev Tu-154s have even flown at low altitude over such sensitive sites as Andrews Air Force Base in Maryland, the US Capitol, the Pentagon, and CIA headquarters in Langley. Starting in May 2020, when Trump first announced the US intent to withdraw, US officials previously said of Open Skies that the US essentially "get nothing out of it" while it potentially exposes national security secrets to broad Russian surveillance. 

Moscow is now throwing up its hands, saying without US participation, it too really gets nothing out of it. "Decades of fruitful implementation of the Treaty on Open Skies showed that it served well as a tool for strengthening confidence and security, creating additional opportunities for an objective and unbiased assessment of the military potential and military activities of the participating States," the foreign ministry emphasized, according to an English translation of the statement in state media.

The new statement puts blame for the collapse of what was meant as a post-Cold War era 'confidence building' treaty (along with the INF Treaty, also dead), squarely on Washington's shoulders.