Regardless of what one thinks about whether using two nuclear bombs on Japan was justified to prevent the loss of hundreds of thousands more in an allied invasion of Japan to end the Pacific war, Oppenheimer's role in building these terrible weapons cannot be minimized. Having organizational skills along with an understanding of physics second to no one is extraordinarily rare but that was what he brought to the table. Working with a whos-who of the very best minds of theoretical physics, they were able to advance the science to a point where a practical application was possible in a very short period and, as we know, worked as planned. His treatment following the war was terrible and totally undeserved. Unfortunately, it has reduced his contributions to winning the war to almost an also-ran level. He is almost forgotten in the history books and that is truly a shame.
In the comments on the page someone linked the actual talk he gave.