From an earlier answer of mine

Most of the early Bundeswehr officers were veterans of the Second World War and quite prominent ones at that. Rommel's former chief of staff in Normandy, Hans Speidel, was one of the main architects of West German rearmament and became one of the chief generals of the Bundeswehr. Adolf Heusinger likewise transitioned from being one of the chief lieutenants of Franz Halder to becoming the head of the Bundeswehr and later one of the chief German representatives to NATO. The postwar Luftwaffe featured many of the aces who were the media darlings of wartime propaganda like Günther Rall, Erich Hartmann, or Walter Krupinski as well as some of the wartime Luftwaffe's command staff such as Josef Kammhuber. Most of the first generation of the Bundeswehr's officers and men had seen service in the war, a fact that did not escape the GDR's propaganda machine such as this DEFA documentary on Speidel.

The postwar career of Heusinger and other Wehrmacht generals like Hans Speidel, Josef Kammhuber, Friedrich Foertsch reflects the wider process of West German rearmament under the auspices of the Adenauer government. Although he was hostile to the spirit of Prussian militarism and leery of the costs associated with rearmament (both fiscal and political), Adenauer saw the rearmament of the FRG as accomplishing two of his major goals for postwar Germany. Firstly, an independent armed force would be a sign that the FRG had regained its own sovereignty. Secondly, Adenauer conceived of the postwar FRG as an integral component of Western Europe. A German military would be an active participant in Western European defense organizations and having a strong German armed presence in Central Europe helped ensure that Western Europe would not abandon Germany to the Soviets to a more defensible line along the Rhine River. The creation of a large professional army quickly helped to precipitate both these agendas.

Since the Adenauer government wanted to establish a new army quickly, this necessitated the involvement veteran German officers and close cooperation with the Western Allied military heads. In the latter case, the former occupation regime was already quite amenable to a German rearmament. In November 1949, Field Marshal Bernard Montgomery and General Lucius Clay co-authored a paper arguing that German military participation was essential for the defense of Western Europe. But beyond public position papers written by former occupation chiefs, a number of officials in Western governments began to perceive West German rearmament as desirable. The JCS had drawn up plans for German rearmament and equipment in light of the Soviet forces in Eastern Europe. The outbreak of the Korean War allowed for the Western governments to openly acknowledge what had been a relatively silent encouragement of German rearmament.

Although Cold War security needs animated Western acceptance of German rearmament, for the officers of the Wehrmacht, rearmament offered them a chance at a greater rehabilitation in the postwar order. As early as the summer of 1945, upper-level German officers were portraying themselves as innocent victims of a criminal Hitlerite regime and that the armed forces of the Third Reich fought an honorable and professional war. The idea of a "clean Wehrmacht" entailed foisting all responsibility for German war crimes onto a narrow clique of Hitler and his collaborators in the SS. The involvement of these officers in planning rearmament allowed them to play up both their professionalism and reestablish the military as one of the foundations of the German state- two major precepts of the clean Wehrmacht narrative.

For his part, Heusinger was emblematic of the image these veterans were trying to construct of the armed forces. Heusinger's aide and later successor as Inspector General, Ulrich Ulrich de Maizière, noted that his chief's:

analyses, based on his analytical reasoning, and his military advice, were marked by a sober objectivity and sober language which avoided any exaggeration, thus came across as convincing. Adenauer too, who in general did not have a good opinion of military men, believed in him and gave him considerable trust. Heusinger possessed understanding of the dependence of military decisions on politics, but no one could accuse him of political ambition. His modest and reserved presence was free from emotion.

De Maizière's encomium about Heusinger incorporated much of the image that German generals sought to present of themselves as a group after the war: able, level-headed, apolitical, and above all, professional. In short, this self-image was the antithesis of the National Socialist regime led by Hitler which was erratic, overly ideological, and incompetent. Heusinger's tangential relationship with the 20 July plotters, which led to a short Gestapo investigation, served to establish his credentials as an opponent of the National Socialist regime but his appearance of professionalism was a connection to German military traditions that the Amt Blank, which had been tasked by Adenauer to lay the foundations for the personnel requirements of rearmament, sought to cultivate.

However, it was seldom a straight line to go from Wehrmacht veteran to Bundeswehr officer. Most senior Wehrmacht veterans that went on to serve in the Bundeswehr has to be cleared through the Personalgutachterausschuss (PGA), a committee set up in 1955 for vetting these applicants for a correct political mentality. Lower-level officer candidates were to be cleared by the Annahmeorganisation (Accepting Organization), which had much less stringent criteria for denazification. Both of these organizations tended to discriminate against veterans of the Waffen-SS and other veterans whose loyalties to the new regime was suspect. Although there was a certain degree of Heer cliquishness at work, the wartime Heer officers tended to regard the Waffen-SS as an organization that substituted ideological fervor for sound training, there was a serious attempt to reform the German military establishment to make it a pillar of German democracy. One of the architects of the FRG's rearmament, Wolf Graf von Baudissin, developed a philosophical-military concept of Innere Führung, in which a subordinate was supposed to keep his head and disobey orders if the situation warranted it. Von Baudissin and other Bundeswehr reformers saw the cultivation of this initiative as an alternative to the blind obedience they blamed for the Wehrmacht's conduct in the Second World War. Although there was some pushback against Innere Führung among the charter generation of Bundeswehr officers, Innere Führung is still one of the major aspects of Bundeswehr military education and it was established in this period.

Naturally, concepts like Innere Führung and the popularization of the clean Wehrmacht myth as exemplified by the publication of von Manstein's Lost Victories, helped make FRG rearmament much more palatable for the West. Although the process was far from straightforward. Both the US and Western Europe initially favored that German rearmament would take places under the European Defense Community (EDC) which would need a much smaller German contingent than the one proposed by Adenauer. The French banked upon a the creation of a EDC as a means to resolve this dilemma. French Premier René Pleven proposed the EDC as a supranational European army which would be headed by a European defense minister in 1950. The Pleven Plan would call for German rearmament to be postponed and reduce Germany's influence by the EDC being an explicitly supranational entity. This was attractive to both Britain and France, but Adenauer refused to countenance any suggestion that Germany was not an equal and sovereign partner. The US tried to act as a mediator between these positions, proposing the Spofford Compromise in 1950 which would limit the FRG contribution to the FRG to 20% of the total force. This compromise became moot when the support for the EDC fell apart when the French parliament rejected the EDC treaty in August 1954. The FRG's entry into NATO in May 1955 became something of a fait accompli in lieu of any practical alternative. Washington under Eisenhower had backed the EDC as a means to expand Europe's defense commitment and render it more efficient than NATO. Eisenhower claimed that suprantional organizations like the EDC were a:

skeleton key, unlocking the solution to a number of problems at once, and most important, providing a type of "dual containment." The Soviet Union could be kept out, and Germany kept in Europe, but with neither able to dominate the Continent.

Although NATO lacked the broad and expansive supranational appeal of the EDC, it was suitable enough to act as such a "skeleton key" for public consumption. Heusinger's appointment to NATO as well as other signs of Bundeswehr participation in the defense system was a sign that the FRG had reformed and was acting as a responsible European partner in the defense against Communism.

The only really prominent vocal opposition to the postwar success of figures like Heusinger came from the Soviets and the GDR. The Eastern bloc press linked economic reorganization and rearmament with Adenauer's strident anti-communism as a sign that this was National Socialism in new clothing. Moscow sent two official notes during the initial soundings for rearmament in 1954, drawing connections between the FRG and "Hitlerite" policies, noting the "serious danger connected with the rebirth of militarism in West Germany and with the drawing of the latter into military groupings."