The Hidden History of How the Marine Corps Made D-Day Possible

June 6 is the 76th anniversary of D-Day and, besides thanking the Sailors and Soldiers who made this operation happen, I also hope you thanked a World War II Marine veteran, because without the amphibious warfare technology developed by the Marine Corps, the landing in Normandy that started the major push into Europe to bring down Adolf Hitler’s Third Reich would have been severely delayed—if not impossible.

Too often, when students and historians study D-Day and the victory over Hitler’s Fortress Europe, they focus on the landings at Omaha and Utah beaches, the Airborne assaults in Normandy, the march of General George S. Patton’s 3rd Army to Germany, or the Battle of the Bulge. Of course, these were major events and worthy of intense study and commemoration. However, few people know that the major reason why the Allies were able to land millions of men against beaches defended by tenacious, well-equipped and well-trained Axis troops was because the U.S. Marine Corps had developed the tactics, technology and experience to employ American power using Higgins boats, amtracs, LSTs (Landing Ships, Tank) and a host of other craft. The Corps worked intensely with the U.S. Navy and Admirals Richmond Kelly Turner and Ernest King to make this happen—and, although we Marines hate to admit this, it was only natural that we worked with the U.S. Navy to develop these ships and tactics for attacking from the sea because we are indeed under the Department of the Navy.

One of the major reasons why the war in Europe, and the Pacific for that matter, came to an end in 1945, and not 1947 or 1948 or even later, was because of the Marine Corps’ focus on amphibious warfare doctrine throughout the 1920s and 1930s. Although the smallest service in the U.S. during the 20s and 30s, the Corps had one of the most important jobs: to develop what would become one of the most commonly used forms of operation by the U.S. Armed Forces during WWII: Amphibious warfare.

To accomplish the feat of perfecting amphibious warfare, the U.S. entrusted much of the preparation for their ocean campaigns to one of the most hot-tempered, tough, perfectionist Marine generals in history, USMC Lt. Gen. Holland M. “Howlin’ Mad” Smith. He was one of the fathers of Marine Corps amphibious warfare. His ideas and foresight about Higgins boats and ship-to-shore tactics were critical for victory against the combined Axis forces, especially when D-Day launched against the Nazi Army stationed in northern France.

After World War I, Smith and his fellow Marines took an acute interest in the major amphibious operations of the Great War, led by the First Lord of the Admiralty Winston Churchill. These amphibious landings against the Ottomans at Gallipoli from 1915 to 1916 were disasters. The poorly equipped, poorly supported and poorly trained Commonwealth attackers suffered 97,000 wounded and 44,000 dead in a losing effort. The Marines learned from studying Gallipoli how not to attack from the sea.

Although Marines had practiced attacking from the sea throughout the Corps’ existence, conducting 160 assault landings before WWII, these operations needed new equipment and tactics. The Corps had a long way to go to perfect techniques that could conduct a successful assault on heavily fortified enemy beaches. Few nations had focused on this at the time, making the U.S. Marines unique.

Before Pearl Harbor, under Smith’s leadership the Marines conducted several landings on the East Coast from U.S Navy destroyers. Those early landings were fiascos, but the Marines learned valuable lessons, especially with problems with ship-to-shore troop deployment. Andrew Jackson Higgins, an inventor from New Orleans and a friend of “Howlin’ Mad” Smith, came up with a solution for conducting ship-to-shore operations that was fast, efficient and simple: the Higgins boat. It was a 36-feet long amphibious craft designed to move men and supplies from large ships to the beach. It could carry 36 men and had a forward ramp that allowed troops to run out of the boat instead of climbing over its sides, a development strongly influenced by Smith’s subordinate, USMC 1st Lt. Victor H. Krulak (he would become a lieutenant general in the 1960s). In fact, USMC Commandant and General Charles C. Krulak (the godson of “Howlin’ Mad” Smith), commenting on his father’s work with Higgins, said, “It was my father who brought to light the importance of the bow launch landing craft and the ability to back off the beach.”

First Lt. Victor Krulak’s reports about similar boats he observed the Japanese use outside of Shanghai in 1937 were actually the deciding factor in educating the by then “Full-Bird” Colonel Smith about the importance of Higgins’ boat design and how it could shape amphibious warfare. With Krulak and Higgins’ prodding and education, Smith realized that the Higgins boat was critical to the Marines’ future success. He, in turn, educated and then convinced U.S. Navy Admiral Ernest King (head of the U.S. Navy) that the Marines needed those boats (the U.S. Army would need these boats too, but it wasn’t yet realized).

America would build 23,358 of these Higgins boats, and the Marines brought this craft to the U.S. Armed Forces, which became one of the most important pieces of technology used in WWII and would carry the bulk of the burden for successful amphibious operations around the globe. Smith said without this boat, “landings on Japanese-held beaches in large numbers would have been unthinkable”—or even impossible.

By the time of Guadalcanal and the North Africa landings (Operation Torch), the Marines had advanced greatly in building out the operational know-how and techniques for America’s missions against the Axis powers.

The Marine doctrine was adopted by the U.S. Army, which republished it in manuals, having never developed an amphibious warfare doctrine of its own. The Marines trained Army officers, who then spread out around the world conducting landings in Alaska, North Africa, Italy, France (D-Day especially), and the Philippines—to name a few. USMC Commandant and General Alexander A. Vandegrift said after the war, “Despite its outstanding record as a combat force in the past war, the Marine Corps’ far greater contribution to victory was doctrinal: that is, the fact that the basic amphibious doctrines which carried Allied troops over every beachhead of World War II had been largely shaped—often in the face of uninterested or doubting military orthodoxy—by U.S. Marines.”

Victor H. Krulak, when he was a member of Smith’s staff, not only helped in the development of the Higgins Boats, but also with amtracs as well. These landing crafts, called “alligators,” were floating tanks or heavily armored treaded vehicles that could land on beaches and drive inland after being dropped into the sea via a ship off shore (20,000 of these were produced during WWII). These two “boats” carried the bulk of the burden for amphibious warfare. You could not have one without the other when conducting landings, because amtracs protected Higgins boats, and Higgins boats brought the riflemen necessary to provide amtracs the support they needed once full ground combat commenced (which, when hitting an enemy beach, happened almost immediately).

After the war, Victor Krulak quoted a study that was even more to the point than Vandegrift’s assessment about the Marine’s main mission throughout the 1920s and 1930s, writing, “Had the Marine Corps not so devoted itself [to amphibious warfare], there would have been no amphibious doctrine for the Army to follow when the threat of war appeared and the Army, when it evidenced its first sustained interest in the amphibious problem in 1940, would have found itself twenty years late.”

Think about D-Day alone—the Germans had one million troops along or near France’s hundreds of miles of northern coastline when D-Day commenced. In order to defeat these forces under Field Marshal Gerd von Rundstedt, Field Marshal Erwin Rommel and General Johannes Blaskowitz, America needed forces that could hit elements of this vast Wehrmacht force manning the numerous defensive beaches, penetrate the enemy’s lines quickly and outflank them to the north and south. The forces that landed at Normandy on D-Day did this and many of the procedures they used, as well as the amtracs, Higgins boats and LSTs deployed, had been developed by the United States Marine Corps.

I want to call out the incredible contributions of USMC Lt. Gen. Graves B. Erskine, who USMC Gen. Anthony Zinni says was the most brilliant Marine Flag Officer of WWII. Although Smith was the visionary of amphibious warfare, it was his Chief of Staff Colonel Erskine who developed much of the guts of how it should be conducted. Erskine explored the details of how Marines and Soldiers should be berthed on a ship before an assault, how amphibious tractors (amtracs) should be used ahead of Higgins boat landings, and how the men should deploy on the beach once leaving their crafts. He developed the procedures on how to ascertain when the beachhead was secured enough by the amtracs and Higgins-borne troops to then bring to the beaches the LCIs (Landing Craft, Infantry—158-foot vessels). The LCIs then could deploy up to 200 troops and all their equipment, and be followed by LSTs (Landing Ships, Tank—382-foot vessels) that could land tanks, jeeps, artillery batteries and trucks from their bow-butterfly doors to provide a second wave of overwhelming power against the enemy. Erskine was Smith’s right-hand man. If Smith was one of the fathers of amphibious warfare, then Erskine was the brain-child visionary who developed that warfare. He would help train and then oversee all the Army officers who conducted the amphibious landings on the Alaskan islands of Attu and Kiska in 1943.

In the end, Erskine was largely responsible for developing operational warfare for the new and more powerful Marine Corps, and the U.S. Army and U.S. Navy one might add, that destroyed Nazi-fortified beaches at Normandy and Japanese-held islands throughout WWII—his fingerprints, if not his whole stamp of approval, were on most of all the major island campaigns in the Pacific.

By D-Day, no organization in the world could conduct amphibious warfare like the U.S. Army, the U.S. Navy and the U.S. Marine Corps. It is difficult to point to one particular historical event that made the difference in the war; however, amphibious warfare was one of the major reasons Nazi Germany and Imperial Japan fell when they did. As historians Philip A. Crowl and Jeter A. Isely concluded: “The most important contribution of the U.S. Marines to the history of modern warfare rests in their having perfected the doctrine and techniques of amphibious warfare [in order] to cross and secure a very energetically defended beach.”

As Supreme Allied Commander at Normandy (D-Day), General of the Army Dwight D. Eisenhower, said, the Higgins boat “won the war for us.” Without it and the Marine contribution to its creation and use, the Allied powers would never have succeeded on D-Day, an operation that sounded the death knell for Nazi Germany 76 years ago this month.

For more about the Second World War, visit bryanmarkrigg.com.