Leslie Groves was a huge bulldog of a man who was known for getting impossible projects done on time and on budget. In Washington D.C., that's nothing short of a miracle. Part of the reason he was capable of performing such wonders was that he had no problem asserting himself in times of adversity.
Groves was a big man, with a big personality—loud, bossy, demanding, quick to criticize. "He had no hesitation in letting others know of his own high opinion of himself," said one former staff member.
Another put it simply: "Groves is the biggest S.O.B. I have ever worked for." (On the Cliff.(8).23-24)
Being such a bossy boss was a major advantage when juggling complex, expensive projects. So even though Groves was disappointed when he was selected to oversee the Manhattan Project (as an army colonel, he really wanted to go overseas to fight, not stay in D.C. as a manager), he was the right man for the job.
His tenacity and willingness to believe that he was right when everyone else was wrong became extremely important when it came to Robert Oppenheimer. Frustrated by the theoretical emphasis in the early phases of the Uranium Committee, Groves realized that while he could handle the logistics, he needed a scientist who could efficiently corral other scientists—and deal with all the scientific unknowns at the same time.
When he met Oppie, he immediately wanted him to lead the brainiacs on his team. Everyone else poo-pooed Oppenheimer for the job because he was famously absent-minded, too feeble to pass an army physical, had little leadership experience, and was a possible communist to boot—but Groves was adamant: Oppie was the man for him.
Later, after Paul Tibbets dropped the bomb on Hiroshima, Groves called Oppenheimer to tell him it was a success:
"I'm proud of you and all of your people," Groves said.
"It went all right?" asked Oppenheimer.
"Apparently it went with a tremendous bang."
"I extend my heartiest congratulations," Oppenheimer said. "It's been a long road."
"Yes, it has been a long road, and I think one of the wisest things I ever did was when I selected the director of Los Alamos."
"Well, I have my doubts, General Groves."
"Well, you know I've never concurred with those doubts at any time." (Reaction Begins.(34).2-8)
This was typical Groves. He knew he was right, and would continue to be right, because he was always right. Sometimes it just takes that level of self-assurance to pull off something like developing the world's first atomic weapon.