American historian Robin Winks says that the "Abwehr" was, "an abysmal failure, failing to forecast Torch, or Husky, or Overlord." English historian Hugh Trevor-Roper says it was, "rotten with corruption, notoriously inefficient, [and] politically suspect." He adds that it was under the "negligent rule" of Admiral Canaris, who was "more interested in anti-Nazi intrigue than in his official duties." Historian Norman Davies agrees with this observation and avows that Canaris "was anything but a Nazi enthusiast". According to Trevor-Roper, for the first two years of the war it was a "happy parasite" that was "borne along...on the success of the German Army." When the tide turned against the Nazis and the "Abwehr" was unable to produce the intelligence the leadership demanded, it was merged into the SS in 1944. Numerous intelligence failures and general incompetence led to catastrophic disasters in both the eastern and western campaigns for the German military. In his book, "The Secret War: Spies, Ciphers, and Guerrillas, 1939–1945," historian Max Hastings claims that other than suborning Yugoslav officers ahead of their 1941 emergency mobilization, the "Abwehr's" espionage operations were "uniformly unsuccessful."