https://www.nytimes.com/2020/05/21/us/p ... ntrol.html
American officials have long complained that Moscow was violating the Open Skies accord by not permitting flights over a city where it was believed Russia was deploying nuclear weapons that could reach Europe, as well as forbidding flights over major Russian military exercises. (Satellites, the main source for gathering intelligence, are not affected by the treaty.)
“You reach a point at which you need to say enough is enough,” said Marshall Billingslea, Mr. Trump’s new special representative for arms control. “The United States cannot keep participating in this treaty if Russia is going to violate it with impunity.”
https://www.foxnews.com/politics/trump- ... ies-treaty
Trump has said in the past that he would only remain in the treaty if China joined, which has not happened.