Now you're thinking I read a book called The Admirals already this year, and you'd be right. But that was a ranking of all the greatest admirals in the Royal Navy. This book called The Admirals is focused strictly on the four 5-star admirals the United States had during World War II. That's not entirely accurate, since none of them were fleet admirals for the majority of the conflict, and Halsey didn't officially reach that rank until December of '45, after the war was over. But William Leahy, Ernest King, Chester Nimitz, and William Halsey are the first four Americans to be given that rank in the Navy, so I guess it makes for a nice connective thread between them.
Borneman moves the retelling of their lives back and forth between them, with some chapters being focused on a specific sort of event - each man's first command, for example - and others relating to a certain span of time during the war. Some chapters focus more heavily on one admiral or the other, as chapters which discuss the ongoing conferences between the Allies tend not to involve Halsey or Nimitz, and the conferences are mostly argument about where to attack Germany. Likewise, when Borneman turns his attention to action in the Pacific, Leahy, serving as FDR's chief of staff, tends to recede. Ernest King is the one who remains a factor throughout, which makes sense as he's the head of the Navy, on the military side at least (which I'm sure he would have contended was the only side that mattered).
I haven't read much about the Navy, so most of this was new to me. There is that recurring American military idea of presenting one's subordinates with an objective, but giving them the leeway to decide how best to achieve it. Nimitz is very good at it, while King certainly espouses the idea, but as he moves up the ladder, he finds it difficult to follow his own suggestion. He does manage it eventually, though he never entirely wrangles his tendency to be abrasive. I suppose the Navy needed someone like that to argue for it, but it hampers him sometimes, mostly with the British. King, and to an extent Halsey, are the types who will go too far in what they say, or how they bend the rules to make a point without realizing it, then have to do damage control to save their necks. Nimitz and Leahy are much calmer, willing to listen, make their arguments forcefully, but accept if things go against them. So Leahy serves as a valuable check on King, and Nimitz can step in to shield Halsey from his worst enemy (other than typhoons), his mouth.
One of the interesting aspects is that all four attended the Naval Academy in the era of the battleship, the Alfred Thayer Mahan school of settling naval conflicts with one massive fight between both sides battleships. Yet Nimitz, King, and Halsey all embraced the potential of submarines and airplanes. In some part, it seems to be a result of those were paths to advancement. Borneman notes that submarines were often a fast path to command opportunities for young officers, and that's how it worked for Nimitz. King likewise saw an opportunity in exploring the potential of aircraft in naval combat, which was an even newer area, and thus even more open for advancement and distinction. As it turned out, submarines and carriers did come to dominate naval combat. The ability to not be constrained by the doctrines they were taught, and the ones that the majority of the people in command staunchly believed in.
One thing Borneman brings up that was curious is that early in the war, Japan had great success using their submarines to attack Allied warships and especially shipping. Then they stopped doing that, using them to deliver supplies to various island bases instead. Borneman can't determine why they did that, since it wasn't a case of the Allies repulsing the attacks with the convoy system, as they were ultimately able to manage with the U-Boats. The Japanese largely gave up the tactic on their own. Curious.
'In undertaking these tasks, Nimitz quickly came to the same conclusion as King. This was to be a different kind of war. The days of Commodore Dewey standing on the bridge of his flagship, leading his fleet into battle, and uttering some pithy remark were over. The numbers of men and ships flung across the sprawling Pacific demanded that nimitz maintain his headquarters at Pearl Harbor, where some measure of central command and control afforded him half a chance of keeping the big picture in mind.'