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 ...

By , a former contributing editor to Foreign Policy.
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. 

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 is a former contributing editor to Foreign Policy. Twitter: @tomricks1

More from Foreign Policy

The USS Nimitz and Japan Maritime Self-Defense Force and South Korean Navy warships sail in formation during a joint naval exercise off the South Korean coast.
The USS Nimitz and Japan Maritime Self-Defense Force and South Korean Navy warships sail in formation during a joint naval exercise off the South Korean coast.

America Is a Heartbeat Away From a War It Could Lose

Global war is neither a theoretical contingency nor the fever dream of hawks and militarists.

A protester waves a Palestinian flag in front of the U.S. Capitol in Washington, during a demonstration calling for a ceasefire in Gaza. People sit and walk on the grass lawn in front of the protester and barricades.
A protester waves a Palestinian flag in front of the U.S. Capitol in Washington, during a demonstration calling for a ceasefire in Gaza. People sit and walk on the grass lawn in front of the protester and barricades.

The West’s Incoherent Critique of Israel’s Gaza Strategy

The reality of fighting Hamas in Gaza makes this war terrible one way or another.

Biden dressed in a dark blue suit walks with his head down past a row of alternating U.S. and Israeli flags.
Biden dressed in a dark blue suit walks with his head down past a row of alternating U.S. and Israeli flags.

Biden Owns the Israel-Palestine Conflict Now

In tying Washington to Israel’s war in Gaza, the U.S. president now shares responsibility for the broader conflict’s fate.

U.S. President Joe Biden is seen in profile as he greets Chinese President Xi Jinping with a handshake. Xi, a 70-year-old man in a dark blue suit, smiles as he takes the hand of Biden, an 80-year-old man who also wears a dark blue suit.
U.S. President Joe Biden is seen in profile as he greets Chinese President Xi Jinping with a handshake. Xi, a 70-year-old man in a dark blue suit, smiles as he takes the hand of Biden, an 80-year-old man who also wears a dark blue suit.

Taiwan’s Room to Maneuver Shrinks as Biden and Xi Meet

As the latest crisis in the straits wraps up, Taipei is on the back foot.