Military planners often create a variety of contingency plans that are often more outlines than specific details. Early in the 20th Century, the Royal Navy had a contingency plan for a war with the USA. Timetables and schedules are prepared for operations but these are tactical and soon go as awry as the plans. Omniscience and perfect intelligence are rare.
Consider the brilliantly planned Overlord effort. During the training phase, an incident at Slapton Sands killed hundreds of Americans who whose bodies (if recovered) were secretly buried in a mass grave. This â€˜training accidentâ€™ never made it to any headlines and is left out of most history books.
There were a lot of errors made during the Normandy Invasion. A lot of Rangers died securing a fortification that was lacking guns. Airborne troops landed in swamps and drowned. Units landed at the wrong place. Fortunately, more mistakes were made on the other side.
While General Eisenhower had a â€˜contingency statementâ€™ to be used if the invasion failed, there was no â€˜complete byâ€™ date for finishing the war.
Imagine if a â€˜drop deadâ€™ date had been announced and made known to the Germans? Even more effort would have been expended and reserves would have deployed in the knowledge that victory needed only be delayed.
Announcing such deadlines is akin to giving aid and comfort to an enemy, especially one that needs not win any victory in the field to defeat a foe that is militarily stronger but weaker in fanatical will.