Your IP access to will expire on June 15

To ensure uninterrupted reading, please contact Rachel Mines, sales director, at

Best Defense

Staff planning: It’s all about examining assumptions and then re-examining them

The planning process customarily begins with the mission. The staff planner has to get right on the planning.



By Lt. Gen. Bernard Trainor, USMC (Ret.)
Best Defense voice of experience

The planning process customarily begins with the mission. The staff planner has to get right on the planning. His available information is initially limited, but he still has to get to work.

He starts the process by cranking in facts and makes educated assumptions to fill in the blanks. As planning proceeds a lot of the initial assumptions are replaced by facts as they become available. But at the end of the process there will be gaps in facts that necessarily have to be filled by rational assumptions. In the final stage of planning (whether of short fuse, e.g. a quick reaction operation or a long, e.g. a major undertaking like an amphibious assault) a good planner will look at the remaining assumptions at the end of the planning process and identify those assumptions critical to the operation. For those he develops alternate plans as close to the original, but which take into account the invalid assumption or assumptions.

Assumptions are frequently like moving trains. That means critical ones must be continually revisited and challenged during the operational phase. Devil’s advocates are never popular, but they are essential to the planning process. A good planner will always be alert to react to any changes.

It seems to me this process is as applicable to the political side as it is to the military. Think of those brilliant assumptions on Iraq. “They will welcome us as liberators.” “We don’t need Phase IV planning” etc., etc., ad nausea.

In developing Courses of Action, here are some thoughts about how to proceed:

— 1. All C/As will be unconsciously influenced by personal bias. Cure: Solicit colleagues choices (i.e. counter bias).

— 2. Staff Estimates of Supportability will always take the most compatible C/A regardless of the rough Concept of Operation. (Cure: After assessing staff choices, solicit views of troop commanders and consider your own when recommending a preferred C/A to the CO — after all you know best what is his intent.

— 3. Immediately upon submitting the customary three C/As to the boss, get to work on C/A, 4., because that’s the one he will decide upon.

The most important tidbit I passed on and disciplined myself to throughout my career was to challenge assumptions. I learned this the hard way as a platoon leader in Korea when I too frequently saw us get whacked, not so much because of faulty or inadequate intelligence (although their was plenty of both), but because of erroneous assumptions made in the absence of fact.

NOTE: Just think of the politico-military blunders this country has made for the past half century, because of accepting assumptions that were convenient (unconscious bias again), when they should have been vigorously challenged. If decision makers from POTUS on down had graduated from CSC at Quantico in the late ’60s things might have turned out differently.

Lieutenant General Bernard “Mick” Trainor USMC (Ret.) is a two war combat commander with over 39 years of service. In retirement he has been military correspondent for The New York Times, a syndicated columnist, director of the National Security Program at Harvard’s Kennedy School of Government, and military analyst with both ABC and NBC. He is also co-author of a trilogy of books on the Iraq Wars.

Image credit: Internet Archive Book Images/University of Toronto/Flickr

Thomas E. Ricks covered the U.S. military from 1991 to 2008 for the Wall Street Journal and then the Washington Post. He can be reached at Twitter: @tomricks1

Trending Now Sponsored Links by Taboola

By Taboola

More from Foreign Policy

By Taboola