The USA has declared its intention to leave the Open Sky Treaty, which is designed to reduce the risk of war allowing Russia and Western countries to conduct observation flights over each other's territory.
Washington informed the other 33 parties to the treaty of its intention to deliver a formal six-month withdrawal notice on Friday, accusing Russia of violations.
"I think we have a very good relationship with Russia, but Russia did not adhere to the treaty and, until they adhere to the treaty, we will leave," Donald Trump told reporters. He added: "There is a very good chance that we will make a new deal or do something to reorganize it."
In a written statement, Secretary of State Mike Pompeo said the United States could reconsider its withdrawal during the six-month notice period "if Russia returns to full compliance with the Treaty". Moscow denies violating the agreement.
US European allies want to maintain the treaty. They benefited from more than 1,500 flyovers under the OST, allowing them to observe Russian military movements and see it as a remaining element of international cohesion and transparency.
"Writing has been on the wall for a long time," said a European diplomat, adding that "it is still disappointing".
The OST is the third arms control agreement that Trump has left. He took the USA out of Nuclear deal with Iran in 2018, and the Nuclear forces of intermediate range 2019. There are fears for the future of the last treaty that limits the strategic nuclear weapons of the USA and Russia, New Start, which is due to expire in February next year, and the Comprehensive Test Ban Treaty, signed by the US (subject to a voluntary nuclear test moratorium), but not ratified.
It is not clear how Russia will react to the US withdrawal. Now they will be able to fly over American bases in Europe, but the US will no longer be able to fly over Russia.
Under the defense spending law of 2020, the government must explain to Congress how to let the OST serve US security interests and ensure that Washington consulted its partners 120 days before formal withdrawal notification.
"The reckless destruction of agreements and the collapse of the US leadership continues," said Kingston Rief, director of disarmament and threat reduction policy at the Arms Control Association.
“The treaty benefits the security of the United States and Europe. Our allies value this and don't want us to leave. It has been an important tool in responding to Russia's aggression against Ukraine. This is a propaganda coup for Moscow.
The United States complained about restrictions imposed by Moscow on overflights that violated the agreement. Russia has limited the flight time of observation flights over the Russian enclave of Kaliningrad and has created an exclusion corridor along the border of Russia's occupied regions of Georgia, South Ossetia and Abkhazia.
"Realize that the Russians were cheating," Tim Morrison, who was briefly the top gun control officer at Trump's White House, said on Twitter. “They were abusing the treaty against the US – as warned military and civilian leaders. The withdrawal denies Putin a collection tool – this is not a victory for him. "
Russia's Foreign Ministry dismissed the infringement allegations as "unfounded" on Thursday and said Moscow had an "alternative plan" in the event of a U.S. withdrawal, but did not provide details.
None of the other parties believed that Russian violations were sufficient to compromise the treaty.
US partners were informed of the decision on Thursday with calls from national security adviser Robert O'Brien, defense secretary Mark Esper and Pentagon undersecretary of policy James Anderson.
"This is insane," was the immediate reaction of Michael Hayden, a former CIA director.
On a joint declaration Earlier this month, a group of 16 retired military commanders and defense ministers said: "Throughout its operation, the treaty has increased military transparency and predictability, helped to build trust and improve mutual understanding."