Everyone understands that the United States, both as a state represented by its embassy, and by the resources that are located there, uses its strength and influence in order to intervene in the domestic political processes in Russia.
Polish authorities were certain of signing an US-Polish agreement on the establishment of “Fort Trump” during the events of the 1st of September 2019. Poland hopes to become an Eastern European Britain. Then, as the most pro-American country, with US support, it could dictate to the rest of the EU what to do and how to do it. These hopes, however, did not come true.
This is a conspiracy consistent with a recurring pro-Kremlin disinformation narrative about US presence in Europe. The US and Poland did indeed negotiate the establishment of a permanent US military base in Poland known as "Fort Trump." It was expected that the two sides would discuss this issue during Trump's planned visit to Poland on 1 September 2019, however, reports did not refer to plans to sign a final agreement on that date. Poland is a sovereign state, which shapes its own foreign and domestic policies - moreover, as a member of NATO and the EU, Poland is able to impact the formation of common foreign policies of these unions. See other examples of the disinformation about Polish-American relations here. See earlier disinformation cases alleging that Poland is the US's "Trojan horse" and is a fully controlled country, that Latvia is a US's vassal state and that Poland plans to establish an anti-Russian buffer zone including Belarus.