Garbage In, Garbage Out


Sea-power theorist Alfred Thayer Mahan warned naval officials, ‘Never divide the fleet!’

Actually, no, he didn’t.

Though routinely ascribed to Mahan, this is an apocryphal quotation. Worse, this truism bowdlerizes his far richer thoughts about concentration and dispersal of force.

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This seemingly trivial error could prompt scholars and practitioners of naval strategy to dismiss a valuable source of strategic guidance out of hand. There’s ample precedent for this. Some historians took Carl von Clausewitz to task for the bloodletting on the Western Front in World War I. Others found fault with Mahan for misshaping Imperial Japanese naval strategy in World War II.

But in both cases, the makers and executors of strategy egregiously misread or distorted the great works they consulted. They—not the authors—bear the blame. Mahan’s works remain relevant to how fleets are built and massed, but they can’t be reduced to simple maxims estranged from the political and strategic circumstances for which he composed them. To do so risks feeding erroneous theoretical guidance into the policy- and strategy-making mill. From faulty input comes faulty output. Call it the garbage-in-garbage-out theory of strategy!

Learned commentators commonly assert that the United States’ ‘Copernicus’ or ‘evangelist’ of maritime strategy did issue a grand injunction against dividing the fleet. Russell Weigley, the author of the standard work The American Way of War, sounds a cautionary, purportedly Mahanian note on US fleet dispositions at the 1944 Battle of Leyte Gulf. Weigley intones that ‘Mahan had warned never divide the fleet,’ and thus that Adm. Bull Halsey erred by breaking away to pursue a Japanese carrier force to the north of the main engagement.

Mahan never used these words. Yet this supposed axiom of naval strategy—utterly abstracted from the context in which Mahan wrote—has found its way into maritime lore. Historian George Baer lodges a similar claim in his masterful history of the US Navy, One Hundred Years of Sea Power: The U.S. Navy, 1890-1990. ‘For Mahan,’ contends Baer, ‘concentration meant massed naval fire, and that meant a fleet. Fleet concentration was the byword; never divide the fleet its corollary.’ But Mahan never stated this corollary in any of his massive tomes.

What did Mahan have to say about fleet concentration? In yet another standard work, Makers of Modern Strategy, Philip Crowl comes closest to putting things in context. Proponents of never divide the fleet generally cite his chapter on Mahan when they provide a citation at all. Yet Crowl can produce no direct quotation, either. Instead he supplies a passage from Mahan’s 1911 work Naval Strategy: ‘(If the Naval War College) had  produced no other direct result than the profound realization by naval officers of the folly of dividing the battle-fleet, in peace or in war, it would by that alone have justified its existence and paid its expenses’ (our emphasis).

That sounds something like never divide the fleet, doesn’t it? But we soon stumble across an important distinction, specifically Mahan’s reference to keeping the battle fleet—not ‘the fleet,’ full stop—together. This is a distinction with a difference. In Mahan’s day a navy’s combat power resided mainly in ‘capital ships,’ which he defined straightforwardly as the vessels best able to dish out and take a punch in a fight with enemy battle fleets. That meant battleships in his vocabulary. But then as now, navies encompassed a host of lesser warships designed not for major combat but for low-intensity or noncombat functions. Such functions typically demand that forces be detached for independent steaming or service with small formations. In today’s terms, think counter-piracy, counter-proliferation and the like.

Never divide the fleet isn’t actionable guidance for a US Navy that’s shouldering multiple missions in many theatres—it would imply jettisoning an assortment of important missions unrelated to major fleet actions. If Mahan had issued such a categorical imperative, he would be justly evicted from the pantheon of strategic thinkers—on this topic, at least.

So should it be never divide the battle fleet? This comes closer, but it still oversimplifies. When Mahan cautioned against dividing the US Navy fleet, he was thinking about dividing it more or less permanently between two coasts, with each segment of the navy largely isolated from the other. Central and South America lay in the way. Reuniting the fleet for battle meant a long voyage for the Atlantic or Pacific squadron. In the interim, the other squadron would confront defeat. Mahan (and fellow naval enthusiasts like Theodore and Franklin Roosevelt) believed such an arrangement would expose both fleets to stronger maritime rivals, inviting disastrous consequences.

In the age of Mahan, the United States wasn’t the superpower we know today, a nation able and willing to pay for multiple fleets spanning multiple theatres. It was a rising but regional sea power with limited resources for shipbuilding. Mahan recalls that in 1909, the US Senate recommended partitioning the navy into Atlantic and Pacific squadrons. He objected to this idea not out of principle—not because the fleet should never be divided—but out of pragmatism. ‘So distributed,’ he proclaimed, ‘the division in each ocean would have been decisively inferior to a foreign battle-fleet there present, to which fleet the two (American squadrons) would have been equal or superior, if united.’

In other words, it made no sense to break up the fleet into detachments that were sure to lose if they duelled a foe like the Imperial German High Seas Fleet or the Imperial Japanese Navy. Better to keep forces combined in one ocean, at the risk of attack in the other, than to subject each squadron to certain defeat—and the US Navy as a whole to piecemeal destruction.

Mahan’s logic remained unassailable until the Panama Canal opened just before his death, allowing the navy to shift forces from ocean to ocean without circumnavigating South America. He was an ardent, longstanding proponent of the canal, which allowed for mutual support between forces in the Atlantic and the Pacific. And in 1940, the United States made the conscious choice to fund two battle fleets, one to face Japan and the other to face Nazi Germany. Mahan would have smiled at the notion that the United States could maintain a superior navy on each coast—as it has since 1945.

So much for never dividing the fleet. We can reformulate the supposed Mahanian maxim thus: Never divide the battle fleet into contingents likely to lose against the enemy forces they are most likely to face. Wordier than the usual version, to be sure, but it offers sounder guidance to fleet building and disposition.

Theoretical wisdom must not be yanked from its historical context—lest mariners pay the price in combat.

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