FYI, a year or so agothere wsa new biography of Paul Tibetts."THe Man Who Won the War"..an excellent book, and a MUST read for anyone interested int he topic..
The Manhattan Project & the Dropping of the Atomic Bombs was the subject of my senior thesis. During the entire time, I only found substantial quotes by one person who brought up the Soviet Union when discussing the atomic bomb. One of Truman's advisers thought its use would make the Soviets "easier to manage" after the war. Of course thinking up stuff like this is the job of people in the War Department (now DoD) so it isn't a surprise something thought it up. Truman however was focused on one thing and that was to end WWII as soon as possible and save as many American and Allied lives.
I was in the Boston area (mid-1990s) when MIT finally tore down the temporary Building 17 that was errected to house the
radar development during WWII.
One of the sayings repeated by the people that didn't want to work on "the bomb" and instead contributed to the radar
project was the "Radar won the war. The atomic bomb ended it."