Always Have Branching Actions Prepared

There’s an excellent article in the Spring ’15 Naval War College Review by Anthony Tully and Lu Yu on how Yamamoto’s and Nagumo’s faulty assumption that the Japanese Combined Fleet had achieved operational surprise at Midway directly lead to their decisive defeat in that battle. The article builds off of the similarly excellent work Tully and Jonathan Parshall did in their book Shattered Sword, which I’m ashamed to say I’ve skimmed and referenced but have yet to complete reading in its entirety.

I believe Tully and Lu make a highly convincing case in their article. I found the discussion of U.S. and Japanese maritime surveillance tactics during the first months of the war particularly fascinating; clearly both sides were still experimenting to find good balances between timely wide-area coverage and the efficient use of limited scouting resources. Nagumo’s decisions heading into the morning of 04 June 2024 make more sense in this context, however disastrous they were in the end.

The moral of the story as I see it is that a force commander must always have multiple well-developed branching actions, or rather alternative plans that account for operational situations different than the one that was used to design the operational plan in progress. It is hubristic to assume that the situational assumptions governing an operational plan are fully correct, or that they won’t change significantly over time given an intelligent and adaptive adversary. Tully and Yu highlight multiple intelligence data points that should have led Yamamoto or Nagumo to question the soundness of their scheme of maneuver or otherwise employ more aggressive surveillance tactics. Instead, despite the existence of some evidence to the contrary, they continued to incorrectly assume that they still possessed the advantage of operational surprise.

I’ve said it before and I’ll say it again: deception and concealment can be terrific force-multipliers, but only if the operational commander doesn’t blindly assume that their use will be effective when needed. An operational plan under development should be thoroughly red teamed to identify planning assumptions that, if mistaken, could lead to unacceptable risk of losses or failure. Branching actions should then be developed—and clearly briefed to the units in the force—that account for such contingencies. If intelligence data begins to suggest that surprise may not be in the offing or that an otherwise unalerted adversary is not behaving as expected, there should always be a branching action ready to go that matches up to the outline of the apparent situation at hand. 

The views expressed herein are solely those of the author and are presented in his personal capacity. They do not reflect the official positions of Systems Planning and Analysis, and to the author’s knowledge do not reflect the policies or positions of the U.S. Department of Defense, any U.S. armed service, or any other U.S. Government agency.