Generally speaking, there were very few service heads inside OKW that pushed for a Mediterranean strategy ahead of the invasion of the Soviet Union. The only real power bloc within the German military establishment calling for such a reorientation were in the Kriegsmarine. Much of the Naval Staff's planning was directed towards defeating Britain and the various war material the Soviets provided severely weakened the British blockade of the continent. Kriegsmarine head Erich Raeder expressed "serious doubts" about OKW's plans for the invasion of the USSR, Operational Directive No. 21, given that Germany was undertaking a massive military operation before the British had been defeated. But Raeder's doubts about Barbarossa need to seen within the context of the polycratic Reich. The navy had been pushing for its own grand reorientation of the German war effort towards the Mediterranean and the Atlantic and looked with alarm the increasing likelihood that America would join the war. The Naval Staff felt that by destroying Britain's Middle East position, they would be able to knock Britain out of the war and further isolate the US. Naval discouragement of Barbarossa does not equate to doubts about the whole enterprise or its justifications. Even Raeder couched his failed appeal to Hitler as a means to secure a successful Barbarossa in 1942. The Naval Staff's chief of operations Rear-Admiral Kurt Fricke produced a memorandum "Observations on Russia" in 28 July 1940 that Soviet expansion in the Baltic was an existential threat to the Reich:

The safety of our homeland, however, also demands in the future the development of spatial unassailability, i.e. an expansion that would prevent any unchecked surprise penetration of vital parts of German soil, a deep forefield . . . which would at the same time provide the necessary living-space for the German nation in the future. . . It moreover demands the greatest possible economic autarky, especially in commodities vital in wartime (e.g. oil, foodstuffs). The further development of Germany requires raw materials and also, to the same extent, markets for her manufactures. For both these purposes Russia is ideally suited . . . The Baltic must become Germany's "Mare nostrum".

This is not to say that German planners were blind to the strategic potential of the triad of Malta, Egypt, and Gibraltar. In the heady days after the Fall of France and Britain's "rejection" of Hitler's offer of peace, there were German plans to undermine the British position in the Mediterranean and the Middle East. The problem was one of allies and in this regard, the Germans were operating at a significant deficit. Much of German war planning in the Mediterranean was highly dependent upon accomplishing these objectives on the cheap and utilizing both Italian and Spanish power to aid Germany's efforts. In an OKW memorandum on the continued war with Britain issued on 30 June 1940, OKW Chief of the Operations Staff Alfred Jodl outlines the basic contours of Germany's strategy to defeat the UK:

The struggle against the British empire can be waged only by, or by way of, countries with an interest in the disintegration of the British empire and with hopes of an abundant inheritance. These are primarily Italy, Spain, Russia, and Japan. Activating these countries is a task for politics. Military support for Italy and Spain is possible on a limited scale (e.g. for mining the Suez Canal or for the seizure of Gibraltar). The Arab countries, moreover, can be given assistance by means of the Abwehr. Most effective would be an Italian offensive operation against the Suez Canal, which, in conjunction with the seizure of Gibraltar, would seal off the Mediterranean.

The problem for Jodl's planning was that few of Germany's potential allies were able or willing to assist Germany in a meaningful way. Notwithstanding the claims of some rather hyperbolic commentators post-9/11 of the success of German propaganda in the Arab world, the Third Reich's appeal to to the Arab mandates tended reaped little rewards and the British were able to crush the few anti-British revolts that did take place like Iraq's in 1941. The Soviets were already beginning to send signals about a rearrangement of the Molotov-Ribbentrop Pact in light of the Fall of France. Despite being amenable to an advance into Southeast Asia, Japanese strategic planning was mired by Army-Navy paralysis and this deadlock would be broken not by German entreaties to join the war, but American embargoes. Although Franco might have been amenable to joining the war, significant elements within his government were not enthusiastic about belligerence and Spain's constant foot-dragging and increasing demands for German aid for an invasion of Gibraltar and fortification of the Canaries ensured that German plans for the Western Mediterranean remained castles in the sky. Italian reverses in Libya and the Balkans in 1940/41 also threw cold water on any thoughts that the Italians could play a substantial role assisting German efforts to undermine the British position. While some of the German military planners' aspersions towards their Italian ally's military capabilities were based on chauvinism, planning for future action had to take into account that Italian forces were seldom as strong as they appeared on paper. Even more disconcertingly for the Germans, one of Italy's strengths, its navy, had proven itself in battles with the RN to be quite deficient. After the Battle of Cape Matapan in March 1941, the German naval liaison to Italy concluded:

That this first offensive operation was such a disaster must be attributed solely to the complete failure of the Italian navy as regards tactical execution, command of formations and ships, and training in the use of weapons.

The liaison report further suggested that German officers and personnel should take command of Italian vessels and staffs (and of course, this was the pot calling the kettle black as the Kreigsmarine also had significant problems coordinating air and sea units and like the Italians, their naval codes were compromised largely due to a situation of the German's own making) .

Therefore German military planning for the Mediterranean between 1940 and 41 often tended to be a mixture of short-term expedients and grand strategy that evaporated in the face of reality. Although Rommel often exceeded his instructions to prevent Italian collapse in Libya and at times revived hopes of a Mediterranean strategy with his successes, DAK could not shake the logic that had set in among OKW and OKH circles that the best way to defeat Britain was to crush the USSR. By late 1941, opinion had shifted against the viability of Operation Felix (the capture of Gibraltar) within much of OKW outside of the Kriegsmarine. OKW had forbid its attaches and officers in Spain from bringing up the capture of Gibraltar with their Spanish counterparts. When the Spanish General José Moscardó Ituarte brought up the subject of invading Gibraltar on 7 December, Hitler told him that Germany had no forces to spare to take Gibraltar. Throughout the latter quarter of 1941, the Kriegsmarine tried to argue that any diversion of troops would be a temporary matter and Felix should proceed, but this assertion fell on deaf ears. Such was the importance of the Eastern front that even in 1942, the planners in OKW became convinced that DAK and North Africa were peripheral to any dislodgement of the British in the Middle East. After a strategic planning conference of 24 October, Walter Warlimont, Deputy Chief of the Operations Staff, produced a memorandum stating:

Because of the course of the campaign in the east, the development of the supply situation in Africa, and the still unclear attitude of Turkey, of the three possible operational directions for the attack on the Middle East (Egypt, Anatolia, and Caucasus-Iran), at the present time the attack via the Caucasus is the most obvious choice.

Warlimont would note that because of this restricted nature of planning due to Barbarossa's failure to result in immediate victory meant that "Gibraltar has been missed [and] must be left to its own devices."

While the sorry state of German planning for the Mediterranean was reflective of the Third Reich's diplomatic isolation, it is important to also note that Germany abandoning the Mediterranean made a good deal of strategic sense from the perspective of the Germans in 1940/41. A Mediterranean strategy would have been dependent upon an Italian naval power that had accrued a string of defeats by 1941 despite operating in its home territory. Going through Turkey was an option, but the mountainous terrain and need for Turkish war materials such as chromium dissuaded German planners from going this route. Most importantly, German planners could not take Soviet neutrality as a given. By 1940, it was becoming increasingly apparent that the Molotov-Ribbentrop Pact was keeping the German war effort afloat and Moscow could withdraw its support for Germany (I have went into the economic aspects of the Pact here ). These limitations on Germany's war effort meant that planning for a wider war in the Mediterranean quickly traveled down a strategic cul-de-sac.

Sources

Militärgeschichtliches Forschungsamt, Germany and the Second World War. Volume III. The Mediterranean, South-east Europe, and North Africa 1939- 1941. Oxford: Clarendon Press, 1995.

_. Germany and the Second World War. Volume IV, The attack on the Soviet Union. Oxford: Clarendon Press, 1998.

Müller, Rolf-Dieter. Enemy in the East: Hitler's Secret Plans to Invade the Soviet Union. London: I. B. Taurus, 2015.