balance. My view.
Start, say, late-1946. Uncle Joe is a good guy. He had paid 25Mn. times to be so. Truman is not a legitimate Pres and we know he will lose in 1948 - certain of that after 1946 mid-term Election. Republicans will hold him to pledge to bring the boys home before 11/48.
UK has a US Loan, and little else except Burden of World Policing, from Trieste, Greece, to Palestine, to India, to strange (under-reported) goings-on in Indo China and Neths. E.Indies. And no Bomb, about to be stolen by Congress.
If...HST had moved Right, towards isolationism, then...all bad guys needed to do was gently wait. France, Belgium, Italy, Iceland had >30% communist votes/MPs.
Now go to late-1947, and we are onway to (where we sat to 1991): ERP, NATO, blocs...and US commitment of warm, largely pink bodies to the cohesion of Free Nations. Now, If Dewey had won, 11/48, who knows...but HST won and poured money and more into making the world the way it is now. UK, especially Bevin-for-NATO, played a part that we may call balancing, but be clear: the commitment of New York to defend York, all-for-one and one-for-all, was sublime, unprecedented.
Was it all a misreading of UJ's objectives? Did he not really mean what his religion says, about exporting the way and the light? Like the Iranis, should we ignore all the bluster for domestic consumption? Well...no. You never can tell.
The single most significant development, learning from history, in post-Cold War times, is the Open Skies transparency extant, NATO:Russian Fedn. Attaches, legitimate spies, sit in SHAPE and in Moscow. Trust...but verify.