Hehe, well first of all, the Allies launched the operation 74 years ago today, not 75 (that would have been the two operations of Husky and Avalanche at Sicily and Salerno, respectively). The answer will be in three parts: background, the argument over the operation, and the operation itself.

Dragoon is a fascinating operation because it involves so many things unique to the ETO experience for the Allies. It gets overlooked for a lot of other reasons.

Background

Operation Anvil, later renamed Dragoon, has not received the attention it deserves in the historiography of World War II. Academic works have seldom covered the operations in southern France. Mentions of the operation are usually made in passing. It is treated as though it was just a footnote in the war. Literature devoted solely to the operation is sorely lacking, and largely devoid of academic credentials. A scouring of several prominent one-volume histories of the war exemplifies this oversight. This is a typical example of the perfunctory coverage of this campaign:

"As this drive towards Paris began, Allied, air, sea and land forces launched Operation Dragoon, landing 94,000 men and 11,000 vehicles between Toulon and Cannes on the Mediterranean coast of France in a single day. Within twenty-four hours these troops had pushed nearly twenty miles inland. That day, in Paris, amid the excitement of the news of this fresh landing, the city's police force, hitherto a reluctant arm of German civic control, agree to put aside its uniforms, keep its arms and join the active resistance on the streets. But the revenge of the occupier was still not ended. That day, five French prisoners, among them de Gaulle's clandestine military representative in Paris, Colonel Andre Rondenay, were taken by the Gestapo to the village of Domont, twelve miles north of Paris, and shot. Their killers had then returned to Paris for an 'executioners' banquet', of champagne." (Martin Gilbert, The Second World War, 568)

By this point in the war, however, tactics were replaced in importance by logistics. General Dwight D. Eisenhower, Supreme Allied Commander, suggests as much. Eisenhower needed as many divisions as he could get on the continent at once, following his broad-front strategy. Acquiring additional ports away from Normandy was the most efficient way to do this. It is this aspect that most historians have tended to ignore. Armies in Italy were unfortunately rendered irrelevant to the operational outcome of the war. The British resented having their main focus in Italy weakened, but forces were transferred from there to Anvil, an operation in which the British had almost zero participation. Operation Anvil was, according to Eisenhower, the most decisive advantage given to the Allies in the struggle with Germany after the Normandy invasion. Its primary value was logistical, in addition to adding hundreds of thousands of troops to the front lines. Anvil was complimentary to Operation Overlord. Just as Batman needs Robin, so too did Overlord need Anvil.

What has emerged is an unbalanced narrative of the western European campaign. In regards to the Normandy campaign, there is a stunning lack of reference to the planning of Overlord in histories of the campaign. Most histories focus on a particular unit or individual segment of the battlefield. When planning is discussed, there is almost a universal lack of reference to Anvil. This was the operation from which Overlord borrowed to make up for a lack of resources. This incomplete picture of the operation is usually followed by a breakout and a race to the Rhine. Nazi Germany's Ardennes offensive in the winter of 1944 caused a setback from inevitable victory, which was achieved in May 1945. A few historians have addressed this imbalance of coverage in recent works.

The fall of 1943 saw the United States repositioning itself among the Allies. For the first year of the war, the United States usually deferred to the British, who had been at war with the Axis for four years. It took until the end of 1942 before the United States began fighting in the ETO. As the Allies slowly advanced through North Africa, the Americans still relied heavily on the British for sound strategic, operational, and tactical advice. Generals Eisenhower and George C. Marshall followed Prime Minister Winston Churchill's lead on attacking peripheral territories held by the Nazis, famously known as the "soft underbelly." Yet, the United States had the largest economy of the Allies, and its numbers were beginning to be felt across the theater. Increasingly the military makeup of the Allies was becoming more American. 1944 promised to be a year in which America would see its star rise higher than anyone else, and Anvil would be a part of that shift. Conversely, Great Britain began to slow down throughout 1943. Its strategic commitments to the empire taxed every resource it possessed. The empire was near the end of its manpower reserves, having detached formations to every part of the globe. Britain welcomed America's material wealth, and expected to dictate affairs, as they were accustomed to doing as a super power. America's leaders began to realize its contributions, and recognized they would only grow within the alliance. As such, they looked to contribute more in a primary way to the direction of the war. This would become clear at Cairo and Tehran, where the Sextant and Eureka conferences would take place. But Great Britain still felt like it should continue to be the driving force behind policy and implementation, and this would complicate Operation Anvil.

Initial planning for Dragoon began in the summer of 1943 in Quebec at the Quadrant conference. This conference is known primarily for the Allies' decision to invade Italy through it's town (Operations Avalanche, Baytown, and Slapstick). Marshall asked Eisenhower for his opinion on operations in Italy and beyond. Eisenhower believed that the invasion of Italy should be used to prepare for an invasion of southern France, although what he called the "annoying and limiting factor of shipping and landing craft" was going to limit any new operations. Eisenhower wanted to use the forces that recently occupied northern Italy, keeping ten divisions there as a defensive reserve; he planned to use the rest to attack westward into southern France.

Next, we'll talk about Allied disagreements over the operation.

Operation Dragoon was one of the smoothest amphibious assaults of the war. The troops were landed with comparatively few casualties, opposition was low, and there was little confusion. The assault force was soon able to move inland, and to seize the major ports of Marseilles and Toulon, while the Germans withdrew in relative disarray.

Planning for an invasion against the south of France began in December 1943, under the codename Anvil. As the name suggests, it was supposed to be carried out at the same time as Operation Overlord, the invasion of northern France. However, it would be delayed, mainly due to British concerns over its effects on the Italian Campaign. The British hoped to use the Italian Campaign to draw off German troops from the French front, and to use Italy as a pathway to the 'soft underbelly' of Europe. General Sir Henry M. “Jumbo” Wilson, Supreme Allied Commander Mediterranean, even suggested that rather than landing in southern France, the Allies land near Trieste, and advance towards Vienna. The Americans, meanwhile, were sceptical about the viability of the British strategy; it would require fighting through difficult terrain, the plan was seen as strongly supportive of British imperialism and interests, and it risked spoiling relations with Stalin. Instead, they wanted to invade southern France to secure the ports there in support of Overlord. Ultimately, the British were convinced of the merits of the American strategy, though not without a certain degree of complaining - the codename was changed to Dragoon because Churchill felt he had been 'dragooned into it'. The final plan was for a three division assault by General Lucian Truscott's VI Corps, to be followed up by the Free French Armee B under the command of Jean de Laitre de Tassigny.

There were a number of pre-invasion operations. From mid-July, the 15th Air Force carried out a heavy campaign against the bridges and railways the Germans would need to move troops to the region. They were joined in this by the French Resistance. By D-Day, 5 of the 6 major bridges across the Rhone had been destroyed by bombing, while another 32 smaller bridges had been knocked out by the Resistance. In the days immediately before D-Day, the 15th AF also carried out strikes against German coastal radars and defences. On the night of the 14th-15th August, a number of assault landings were carried out to destroy German coastal batteries that threatened the main landings. The American-Canadian First Special Service Force landed on the islands of Ile du Levant and Port-Cros. Neither landing met much resistance as they went ashore. On Ile du Levant, the objectives were captured quickly but the coastal guns were found to be dummies. On Port-Cros, the commandos were held up by German forces dug in in three Napoleonic-era forts, which did not surrender until the 17th August. 700 French commandos of the First Group Commandos Afrique were landed at Cape Nègre under Operation Romeo. They missed their assigned beach due to currents, and came ashore under heavy German fire. However, they were able to destroy the coastal guns there, and seize the roads inland shortly after dawn, thanks to heavy support from the cruisers Dido and Augusta. The last major pre-invasion landing was the airborne attack, carried out by the 1st Airborne Task Force, a joint Anglo-American force. While the Allies had learned well from the Normandy landings, they could not control the weather. The pathfinders, dropped before the main assault to mark landing zones, ran into heavy fog. As a result, the landings were heavily scattered; only 40% of the troops landed near their intended drop zones. This did have the unintentional effect of causing the Germans to overestimate the numbers of Allied paratroopers landed, and hence drew troops away from the beaches. The follow-up gliderborne troops, landing later in the morning, avoided the worst of the fog but ran into trees and anti-glider defences. This resulted in heavy casualties, with 283 men being killed or wounded during this phase. There were a number of diversionary operations. Dummy paratroopers were dropped at La Ciotat, further confusing the Germans. A naval diversion was carried out in the same area, with 21 small craft supported by the destroyer Endicott using radar reflectors and sound effects to suggest the appearance of a landing force there. Another similar diversion was carried out off Antibes. The performance at La Ciotat was repeated on the 16th-17th, this time provoking heavy German fire. On the morning of D-Day, a further diversion was carried out by a unit commanded by Lt. Cdr. Douglas Fairbanks Jr, which involved the landing of 67 French commandos at Pointe de l’Esquillon. The landing was a failure, as the French troops immediately encountered a minefield before being pinned down by heavy German fire. The commandos were captured by the Germans, but later freed by the French Resistance.

The main assault was carried out in three sectors, each attacked by a separate division of VI Corps. The 3rd Infantry Division had the western-most sector, Alpha, which encompassed Cavalaire sur Mer and St Tropez. The 45th Infantry Division landed in the central sector, Delta, which covered the areas around Sainte-Maxime. Finally, the 36th Division brought up the right flank, landing in sector Camel around Frejus and Saint Raphaël. I will cover each of these sectors in turn.

The 3rd Division was to be landed in the most critical sector. It was closest to the main objectives of Toulon and Marseilles, and was expected to face strong German counterattacks. However, the main initial threat was from German mines and coastal obstacles. The assault was preceded by a strong minesweeping force of 22 ships, plus a number of landing craft modified to serve as shallow-water sweepers. These cleared the route into the beaches, though few mines were actually found. The minesweeping effort was followed by a heavy air and naval bombardment, running from 6:15 to about 7:30. As the bombardment was ongoing, Allied forces were beginning to clear the beach obstacles. 'Apex' boats - radio-controlled LCVPs loaded with 8000lbs of explosives - were used to blow holes in the beach obstacles, before obstacle clearance teams were landed. Rocket-launching landing craft fired on the beach, hoping to detonate mines. Following all this, the assault troops went in at two separate beaches; Alpha Red in Cavalaire Bay, where the 7th Infantry Regiment landed, and Alpha Yellow near Pampellone, assaulted by the 15th Infantry Regiment. These two regiments were faced by a single battalion of German troops (using the term very lightly, as they were mainly 'Osttruppen', Soviet prisoners of war pressed into Wehrmacht service). At Alpha Red, the 7th encountered sporadic small arms fire, with the main threat coming from mines and artillery fire. Two LCVP were lost to mines with sixty casualties ensuing, but the troops were quickly moving inland. An hour and twenty minutes after the first troops of the 7th landed, the 30th Infantry Regiment was starting to come ashore - this swift landing of fresh troops showed how easy the landing had been. At Alpha Yellow, the experience was similar. The sole mishap came when control of one of the Apex boats was lost, causing it to explode near the motor launch SC-1029, causing heavy casualties aboard. French Resistance forces and local residents came out to assist with the clearing of the beach obstacles, while the troops pushed inland. In the afternoon, elements of the 15th linked up with misdropped paratroopers from the 509th Parachute Battalion and French Resistance forces to capture Saint-Tropez, the main objective for the day. By the end of the day, the 3rd Division had taken 264 losses, and captured 1627 German soldiers.

Delta Sector was thought to be the most well-defended sector, with heavy gun batteries that could bring the beaches under a deadly crossfire. As such, it had the heaviest offshore support element, consisting of two American battleships (Nevada and Texas), an American cruiser (Philadelphia), two French cruisers (Georges Leygues, nicknamed 'Gorgeous Legs' by the RN, and Montcalm), three large French destroyers and eight American destroyers. The bombardment force opened up a heavy fire on the German gun batteries and coastal defences, albeit one hampered by fog and haze. The Germans responded with desultory fire. The landing ships went in at four beaches, Delta Red, Green, Yellow, and Blue, preceded again by Apex boats and rocket barrages. The overwhelming Allied firepower successfully suppressed the defences, to the point where the landing at Delta Red suffered only a single casualty from the assault battalion. The troops marched off the beaches and began securing the surrounding area. The 157th Infantry Regiment secured Sainte-Maxime with relative ease. The 180th Infantry Regiment secured the high ground behind the beaches with little trouble, but encountered significant German resistance as it began to push towards Saint-Aygulf. Other elements of the division linked up with the paratroop airhead, and helped the paras capture Le Muy. The division suffered just 183 casualties over the course of the day. The only naval casualties in the sector were the crew of LST-691, who suffered food poisoning after eating improperly refrigerated sandwiches.

Following up on this, what did the Allies hope to gain from invading France from the south after already gaining a firm foothold in Normandy?