Truman became president on April,12 1945. He was given a full briefing on the Manhattan project on April 24,1945. That doesn’t seem like he was being kept in the dark.
It was one of the most important and costly projects of the war, 12 days is a lifetime during a war quite literally. That’s also ignoring the fact that the vice president was kept in the dark until after FDR died and Truman took office.
That was the full briefing and Truman had been told about it earlier. And him not being told while he was vice president is irrelevant to information being withheld from a president.
That’s dated April 24.
It’s not, the administration by in large knew FDR was dying and would likely die before leaving office. Truman effectively was a president in waiting rather than a vice president.
