It should be noted that later in life Keenan was distraught by the extreme anti-communist hysteria and need for containment that was inspired by his telegram and general foreign policy views [0]. It seems that postwar US was much more cordial and trusting of the Soviet Union but quickly swung to other side as it became clear that Stalin was interested only in grabbing as much land as possible to form a sizeable buffer between Russia and western Europe. Which seems reasonable: German forces had reached the outskirts of Moscow and an unbelievable number of Russians died in the war.

I highly highly recommend the Wise Men [1].

[0]: https://en.wikipedia.org/wiki/George_F._Kennan#Academic_care... [1]: https://www.amazon.com/Wise-Men-Friends-World-They/dp/147672...