Let us recall that the “Open Skies Treaty” which has been ratified by 34 states, sets up a program of unarmed surveillance flights over the entire territory of the states participating in the treaty.
It aims to strengthen understanding and mutual trust by giving all its participants, regardless of their size, a direct role in gathering information about military forces and related activities. “Open Skies” is one of the most far-reaching efforts at the international level to promote openness and transparency in this area. The US announced its withdrawal on May 22, 2020. This is not the only treaty that the US is withdrawing from. There is also the Iranian nuclear program, denounced in 2018, and the treaty on land-based medium-range missiles, abandoned in 2019.
Several European countries, including France, Germany, Belgium and Spain, regretted this decision while saying they shared American concerns "relating to the implementation of the provisions of the treaty by the Russian Federation". For its part, the Russian Federation spoke through its Minister of Foreign Affairs who said in essence:“Washington has taken action. Neither European security, nor that of the United States and its allies wins. Now many in the West are wondering about the possible Russian reaction. The answer is simple. We have previously stressed on several occasions that all possibilities are open to us. We closely monitor and analyze the correspondence between the words of other treaty participants and their actions. We are therefore going to take decisions that are consistent with Russia's security interests”.
The withdrawal of the USA from numerous treaties and international organizations, such as recently from the WHO, but also from the “Paris Agreement on Climate Change”, from the “Original Transatlantic Partnership”, from the “Joint Comprehensive Plan of Action JCPOA "...All of this is not fortuitous, but the result of an international balance of power that is evolving to its detriment, of a strategy allowing it to have a free hand with both its adversaries and its allies. This can be seen with Trump’s treatment of NATO, of which he intends to remain the only master on board.
This "emancipation" from international law, painfully resulting from the Cold War and from a balance of power which the USSR had been able to impose, is summed up by the slogan "America first". This slogan is found in both the Democratic and Republican parties. Basically, it reflects the decline of the United States and the fact that it can no longer impose global leadership on the world. Conversely, China and Russia, and especially China, have a pressing need for "international law" to legitimize a rise in power and ensure their growing influence as autonomous strategic players. Thus for example, China continues to proclaim its commitment to free trade as an essential condition for the development of the world economy... and especially its own. The latest example, its role in the signing of the free trade treaty which covers a large part of Asia and the Pacific area.
(https://www.sitecommunistes.org/index.php/monde/asie/1152-asie-une-nouvelle-union-de-libre-echange-capitaliste).
It is therefore clear that the attitude of the USA has nothing circumstantial and does not result from the "whim" of a president, but in view of the confrontation and competition within the imperialist system, it denotes the evolution of the balance of power.