At the outbreak of World War II, he was the G-2 Officer (Intelligence) and then G-3 Officer (Plans and Training) of the 1st Infantry Division from March 1941 until June 1942.
In June 1942, he was promoted to chief of staff of the division, a position he held until February 1943.

In February 1943, right after his involvement in the Allied invasion of North Africa, under the command of Major General Terry Allen, he prepared a report which included suggested revisions to the task organization of assault divisions, and his recommendations were adopted during preparations for Operation Husky, the codename for the Allied invasion of Sicily.
He was promoted to the one-star general officer rank of brigadier general and was quickly sent to the United Kingdom, where he served as the American advisor to the Combined Operations Division of the European Theater of Operations.
In that capacity, Cota helped supervise the training for amphibious landing operations.

As a major advisor in Operation Overlord, he was made the assistant division commander of the 29th Infantry Division, which was designated to land at Omaha Beach during the Battle of Normandy.
The 29th Division, a National Guard formation nicknamed the "Blue and Grey", was commanded by his fellow West Point classmate, Major General Charles H. Gerhardt.
During the planning for D-Day, he opposed daylight landings, believing a pre-dawn assault would stand a better chance of success.
A year before the invasion, at the Conference on Landing Assaults, Cota had argued in favor of striving for tactical surprise:
. . .
It is granted that strategical surprise will be impossible to attain.
Tactical surprise is another thing however... .
tactical surprise is one of the most powerful factors in determining success.
I therefore, favor the night landing.
I do not believe the daylight assault can succeed.

Cota was not alone in his opposition.
Major General Leonard T. Gerow, commander of V Corps, and Admiral John L. Hall, Jr., commander of Amphibious Force "O" (the naval force responsible for delivery of the 1st Infantry Division to the beach), both fought to change the Operation Overlord plan, pleading for a nighttime assault.

However, the high command decided otherwise, concluding that naval and air bombardment would hopefully neutralize, or in the best case, eradicate, enemy opposition.
The plan for Omaha essentially called for hurling infantry directly at a prepared enemy position, a position that was enhanced by the concave shape of the beach (effectively promoting enemy crossfire into the "basin" of the concavity), natural and man-made obstacles, bad weather and other factors.

Most D-Day commanders assured their men that the Germans would be annihilated by the Allies' pre-invasion firepower, and that the defenders were, in any case, outnumbered, inexperienced and demoralized.
All of these beliefs were to be proved woefully inaccurate.
On the afternoon of June 5, Cota gave an accurate assessment to the staff of the 29th Infantry Division:
This is different from any of the other exercises that you've had so far.
The little discrepancies that we tried to correct on Slapton Sands are going to be magnified and are going to give way to incidents that you might at first view as chaotic . . .
You're going to find confusion.
The landing craft aren't going in on schedule and people are going to be landed in the wrong place.
Some won't be landed at all . . .
We must improvise, carry on, not lose our heads.

While Cota had a far less optimistic view of the plan than the high command, even he underrated the extent of the near-catastrophe that awaited V Corps (composed of the 29th Infantry Division and the famous "Big Red One" 1st Infantry Division) on Omaha Beach.

Cota landed with a part of the 116th Infantry Regiment, part of the 29th Division, in the second wave, approximately one hour after H-Hour on the Omaha sector known as Dog White.
His LCVP landing craft came under heavy machine-gun fire as well as mortar and light artillery fire; three soldiers were killed immediately upon leading the disemb
At the outbreak of World War II, he was the G-2 Officer (Intelligence) and then G-3 Officer (Plans and Training) of the 1st Infantry Division from March 1941 until June 1942. In June 1942, he was promoted to chief of staff of the division, a position he held until February 1943.
In February 1943, right after his involvement in the Allied invasion of North Africa, under the command of Major General Terry Allen, he prepared a report which included suggested revisions to the task organization of assault divisions, and his recommendations were adopted during preparations for Operation Husky, the codename for the Allied invasion of Sicily. He was promoted to the one-star general officer rank of brigadier general and was quickly sent to the United Kingdom, where he served as the American advisor to the Combined Operations Division of the European Theater of Operations. In that capacity, Cota helped supervise the training for amphibious landing operations.
As a major advisor in Operation Overlord, he was made the assistant division commander of the 29th Infantry Division, which was designated to land at Omaha Beach during the Battle of Normandy. The 29th Division, a National Guard formation nicknamed the "Blue and Grey", was commanded by his fellow West Point classmate, Major General Charles H. Gerhardt. During the planning for D-Day, he opposed daylight landings, believing a pre-dawn assault would stand a better chance of success. A year before the invasion, at the Conference on Landing Assaults, Cota had argued in favor of striving for tactical surprise:
. . . It is granted that strategical surprise will be impossible to attain. Tactical surprise is another thing however... . tactical surprise is one of the most powerful factors in determining success. I therefore, favor the night landing. I do not believe the daylight assault can succeed.
Cota was not alone in his opposition. Major General Leonard T. Gerow, commander of V Corps, and Admiral John L. Hall, Jr., commander of Amphibious Force "O" (the naval force responsible for delivery of the 1st Infantry Division to the beach), both fought to change the Operation Overlord plan, pleading for a nighttime assault.
However, the high command decided otherwise, concluding that naval and air bombardment would hopefully neutralize, or in the best case, eradicate, enemy opposition. The plan for Omaha essentially called for hurling infantry directly at a prepared enemy position, a position that was enhanced by the concave shape of the beach (effectively promoting enemy crossfire into the "basin" of the concavity), natural and man-made obstacles, bad weather and other factors.
Most D-Day commanders assured their men that the Germans would be annihilated by the Allies' pre-invasion firepower, and that the defenders were, in any case, outnumbered, inexperienced and demoralized. All of these beliefs were to be proved woefully inaccurate. On the afternoon of June 5, Cota gave an accurate assessment to the staff of the 29th Infantry Division:
This is different from any of the other exercises that you've had so far. The little discrepancies that we tried to correct on Slapton Sands are going to be magnified and are going to give way to incidents that you might at first view as chaotic . . . You're going to find confusion. The landing craft aren't going in on schedule and people are going to be landed in the wrong place. Some won't be landed at all . . . We must improvise, carry on, not lose our heads.
While Cota had a far less optimistic view of the plan than the high command, even he underrated the extent of the near-catastrophe that awaited V Corps (composed of the 29th Infantry Division and the famous "Big Red One" 1st Infantry Division) on Omaha Beach.
Cota landed with a part of the 116th Infantry Regiment, part of the 29th Division, in the second wave, approximately one hour after H-Hour on the Omaha sector known as Dog White. His LCVP landing craft came under heavy machine-gun fire as well as mortar and light artillery fire; three soldiers were killed immediately upon leading the disemb
Norman Cota