Thomas was born in
Forst (Lausitz),
Brandenburg. Thomas joined
Infantry Regiment 63 as an ensign and a career soldier in 1908. From 1928, he dealt with
armament questions at the (Army Weapons Office) in the
Reich Defence Ministry in
Berlin. From 1928 to 1938, Thomas worked as the Chief of Staff for the Army Weapons Office in the Reich Defence Ministry, where he studied national economics and war preparations, pushing forward the idea of a "defense economy", the accumulation of Germany's resources for the purpose of war under a central planning commission. It is speculated he did not resign to foment plans for a coup. In 1939, he became head of the Defence Economy and Armament Office in
Oberkommando der Wehrmacht (OKW, high command of the armed forces). He was a member of the board of
Kontinentale Öl AG (an oil company whose purpose was to exploit
petroleum resources in occupied countries) as well as
Reichswerke Hermann Göring, an
iron and
steel company. Thomas worried about an attack provoking the British and French, as were generals
Walther von Brauchitsch, Colonel-General Halder and the Quartermaster General von Stülpnagel, yet Hitler refused to countenance delay or accept reluctance from his military staff about his plans as Fuhrer and more earnestly pushed forward the arguments for an attack, despite the collective arguments otherwise by Hitler's generals. During the planning of Barbarossa (the invasion of Russia), General Thomas' pragmatic and realistic nature once again gripped him. Thomas thought a full-scale war with the Soviet Union should be delayed until the logistical concerns were remedied. He informed Colonel-General
Franz Halder, the Chief of the OKH General Staff, that the attack on the Soviet Union would experience logistical delays due to the fact that Russian railways were of a different gauge than German ones. Thomas also warned Halder of the insufficiency of German transport vehicle tires for the task ahead of them, and most significantly, Thomas revealed to Halder that the Germans only had two months' worth of fuel oil and petrol for the invasion. Inexplicably, Halder did not convey this information to Hitler and when Thomas tried to, Field Marshal
Wilhelm Keitel suppressed the report. Reassurances soon made their way to General Thomas when the
Reichsminister,
Hermann Göring, told him not to worry about using Germany's resources since "they would soon be masters of France, Belgium, and the Netherlands", adding that they would plunder resources in the "captured territories". In November 1942, Thomas resigned from the Defence Economy and Armament Office.
Albert Speer and his Armament Ministry had taken over almost all the expertise relating to armament policy. Of note, during the autumn of 1943, Hitler asked for a forecast of what the Germans might expect in the near future. The Chief of the Operations Staff for the OKW, Colonel-General
Alfred Jodl, submitted the report to Hitler but he became irate when the estimates were given to him, mentioning Thomas, who "rated the Soviet war potential as high". Hitler forbade war studies by the OKW. Apparently Thomas tried several times to bring the German General Staff and Hitler back to reality. Thomas's pragmatism might have contributed to his disillusion with the regime, perhaps leading him to believe that a coup was necessary to stop Germany from being annihilated. == Resistance to Hitler ==