Best Defense

Thomas E. Ricks' daily take on national security.

A few words in favor of the much-derided individual replacement system for soldiers

As MajRod knows, I sometimes like to take a look at icons like readiness and ask, Do we really need to do it that way? I especially like to do that on Fridays so we can talk about it over the weekend. But I am doing it today because I don’t plan to post on ...

U.S. Army
U.S. Army
U.S. Army

As MajRod knows, I sometimes like to take a look at icons like readiness and ask, Do we really need to do it that way? I especially like to do that on Fridays so we can talk about it over the weekend. But I am doing it today because I don't plan to post on Thanksgiving or the day after. 

So I was pleased to read an essay on the individual replacement system by Robert S. Rush, the only retired command sergeant major I know who has a Ph.D. from Ohio State, one of the best military history departments in the country. Now, "everyone knows" that, just as readiness is "good," so is unit rotation. Or at least that unit rotation is better for cohesion, and so for military effectiveness, than the stinking individual replacement system used in World War II and Vietnam.

Or so I thought. Then I read CSM Rush's essay "The Individual Replacement System: Good, Bad or Indifferent?" (It was presented at a conference about 10 years ago, but I don't believe it has been published.) Among his surprising findings, based on an intense study of the replacement system in the U.S. Army in Europe in late World War II:

As MajRod knows, I sometimes like to take a look at icons like readiness and ask, Do we really need to do it that way? I especially like to do that on Fridays so we can talk about it over the weekend. But I am doing it today because I don’t plan to post on Thanksgiving or the day after. 

So I was pleased to read an essay on the individual replacement system by Robert S. Rush, the only retired command sergeant major I know who has a Ph.D. from Ohio State, one of the best military history departments in the country. Now, "everyone knows" that, just as readiness is "good," so is unit rotation. Or at least that unit rotation is better for cohesion, and so for military effectiveness, than the stinking individual replacement system used in World War II and Vietnam.

Or so I thought. Then I read CSM Rush’s essay "The Individual Replacement System: Good, Bad or Indifferent?" (It was presented at a conference about 10 years ago, but I don’t believe it has been published.) Among his surprising findings, based on an intense study of the replacement system in the U.S. Army in Europe in late World War II:

  • "Units fail most often when not maintained at strength, not because the soldiers lack long-term bonds with one another."
  • "Units are more combat-efficient when there are combat-wise veterans within the unit."

His bottom line is worth quoting at length:

  • "Success results NOT from rotating organizations in and out of combat but from sustaining those organizations while in combat. Battalions fighting at near battalion strength can accomplish missions that battalions fighting at company strength cannot, even when it is a company of grizzled warriors. It is only when the veteran cadre is sustained by a continual influx of new soldiers who in turn coalesce around this battle-hardened core that a unit’s combat power increases."

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 ricksblogcomment@gmail.com. Twitter: @tomricks1

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