In finishing the book Sea of Thunder by Evan Thomas, I was amazed at how many assumptions and mistakes were involved in the Leyte Gulf campaign that ended in the deaths of thousands of sailors on just our side:

  1. Admiral Halsey assumed that Admiral Kinkaid and his destroyers and aircraft carriers could handle the threat of both the Japanese attacking fleets (Adm. Kurita & Adm. Nishimura),
  2. Halsey assumed that Adm. Kinkaid had received and understood his dispatch that the Japanese were returning back through the San Bernardino Straight,
  3. Kinkaid assumed that Halsey had left his ‘Task Force 34’ at the entrance of San Bernardino Straight,
  4. Halsey and his intelligence staff overlooked the Japanese ‘Plan Z’, and the misdirection it called for, in chasing after Ozawa to the North, leaving the Seventh Fleet unguarded from the North,
  5. Capt. Mike Cheek, Halsey’s staff intelligence officer, didn’t press his opinions strenuously enough due to his extremely reserved nature,
  6. Due to the divided command between Nimitz and MacArthur, messages couldn’t be transmitted directly between Kinkaid and Halsey, but had to be relayed through a radio station 1,000 miles away and added a 1-2 hour delay between transmission and receipt,

I’m certainly not second-guessing the men who fought and led our side in WWII. As Evan Thomas put it, “Who can know what it is really like to stand, bone-weary, on the bridge of a ship in action, responsible for hundreds if not thousands of lives, unsure of the enemy’s strength and whereabouts, yet forced to make fatal decision?” (p. 354). The ‘fog of war,’ exhaustion, and sickness all led to the mistakes in the battle of Leyte Gulf. In the end, Halsey’s decision to chase the Japanese carriers to the North robbed him of the one thing he had been wanting all his life, a major sea battle. But his decision cost the lives of thousands of US sailors.

It’s a good reminder to those of us in business to always question assumptions. The stakes aren’t as high as in war, and most of the time someone’s life is not at risk. But assumptions can destroy a company, or leave it limping so severely as to be unable to compete. I’ve been in situations where my assumptions came back to bite me in the end. Luckily, when I have made assumptions, it hasn’t led to serious consequences, but I learned my lesson and always try to think through the situation and look for those hidden assumptions.


One thing I’ll add upon reflection, is how much the mistake Halsey made tore him apart. The author does a good job of showing how much he cared for the men who served under him, and how much it hurt him to sign orders where he knew men would die.

— Thomas, E. (2006). Sea of Thunder. New York, NY: Simon & Schuster.