If you ignore the US invasion of Siberia in 1918 during the Russian Civil War, 1949 marks a good starting point for US meddling in Ukraine in order to facilitate regime change in Moscow. Operation Red Sox was a failure, but fifty years later the USSR collapsed and western investors saw a huge payday in the former Soviet Union; they are still looking for their next big score in that part of the world:
https://www.politico.com/news/magazine/2022/05/11/covert-operation-ukrainian-independence-haunts-cia-00029968
"In late 1949, a series of unmarked flights began launching from central Europe. Gargantuan C-47s, flown by Hungarian or Czech pilots, barreled toward Turkey, and then turned north over the Black Sea, evading radar by flying barely above the ground.
"As the planes flew over Lviv a string of parachutes opened, a handful of commandos tumbling into the sky over Soviet Ukraine.
"On the ground, they linked up with Ukrainian resistance fighters trying to beat back Soviet expansionism.
"Operation Red Sox, as it was known, was one of the first covert missions of the still new Cold War."