Preliminary Planning for the “Longest Day”

Following the decision at the Casablanca Conference (January 1943) to undertake an invasion of northwestern Europe, British Lt. Gen. Frederick Morgan was made Chief-Of-Staff (COS) to the not yet appointed Supreme Allied Commander (SAC) to begin planning for the operation.

In COSSAC, independent scholar and former U.S. Marine Kepher takes the first serious look at Morgan’s life and career, the organization he created, and its work. In its nine months of existence, Morgan’s organization examined and resolved virtually every problem the invasion posed, while creating a closely integrated Anglo-American staff.

This work proved invaluable to Dwight Eisenhower when he was appointed SAC at the end of 1943. While subsequent planning made some changes to the COSSAC plan, notably in expanding the invasion “Front” from three divisions to five, it was more a matter of refining COSSAC’s work than of breaking new ground.

Many years after the war Eisenhower commented that “Plans are worthless, but planning is everything”, because good planning touches on what may happen when your plans go awry -- as they surely will -- and in COSSAC, a volume in the Naval Institute Press series “Studies in Naval History and Sea Power”, Kepher does a very good job of explaining why the landings and campaign that began on D-Day proved successful.

---///---

Note: COSSAC is also available in several e-editions.

StrategyPage reviews are published in cooperation with The New York Military Affairs Symposium