Apparently almost every president had a foreign policy doctrine. One even got it’s own teaching bloc in public schools, at least until the 1980s. It was called the Monroe Doctrine, which stated that the US would use force to repel foreign (mostly European) incursions into the western hemisphere.
The Monroe Doctrine was a big deal. We used it to expel Spain from Cuba in 1898. In 1962 JFK invoked it to justify blockading Soviet ships sent to Cuba to set up nuclear missile silos there.
But after World War II, American “spheres of influence” expanded because of Soviet expansionism in eastern Europe and Asia, which accelerated even before the ink was dry on the German and Japanese surrenders.
The Soviets were way ahead of us in their post-war strategic thinking.
During World War II, there was no real FDR Doctrine except to win “the wahr”, which he did not live to see end. But at Yalta in February,1945, with Berlin virtually surrounded by their armies, FDR, Stalin and Churchill sat down to decide what to do about the several nations the Red Army had “liberated” in the East, especially Poland, who had a deep personal relationship with Churchill throughout the war. (Winston would have to throw them over.)
FDR gave the Red Army-occupied east European nations (soon to be called “Bloc”) away to Stalin, although no one is exactly sure why. It might have been a consolation gift since Stalin was complaining from Day One, once America finally entered the war a year and a half after Germany had attacked Russia, that we hadn’t started a second front in the West quickly enough.
(I always think of this when I hear feminists whine, wondering where they learned it.)
With crocodile tears that still get to liberal Democrats when they encounter a totalitarian with a kindred philosophy, FDR had already given thousands of Soviet agents carte blanche access to virtually every government agency in the US for nearly four years. From these they built cells everywhere, especially in departments where there was philosophical simpatico, such as the State Department. Stalin sent Russian choirs, folk dancing groups and artists (I collected their music and the art) while we, in turn, let them look at our blueprints for bombers, machine guns, and flush toilets. (They were already ahead of us in tanks.)
They even knew about The Bomb, but it would be 1949 before they could test their own. And even though we had intercepted their codes midway through the war, we were still clueless that our pockets had been picked at Yalta until they dropped their bomb.
This is why Joe McCarthy went on a Red-Scare rampage[…]