After the seizure of power by the Nazis Backhaus met Adolf Hitler, no later than May 1933, while flying with him to Munich. That same year, he became executive advisor to the Nazi organization Kameradschaft der deutschen Künstler. For the show elections of 29 March 1936, Backhaus published a statement in the magazine Die Musikwoche under the rubric of "soloist" translated as, "Nobody loves German art, and especially German music, as glowingly as Adolf Hitler…" A month later, on 20 April 1936, Hitler's 47th birthday, he gave Backhaus a professorship, and invited him that September to attend the annual Nazi party's Nuremberg Rally. The violinist Leila Doubleday Pirani wrote that in November, 1938 she attended a Backhaus concert in London with the Viennese Jewish violinist Alma Rosé, who told Pirani that Backhaus "was a great friend of the family" and took her backstage to greet the pianist after the concert; but Pirani writes that while "Boult greeted us nicely," Backhaus, upon seeing Rosé, "turned his back and walked through a passage"; Pirani called the incident "a stab in the back by this cowardly man, who for fear of his Nazi masters could not behave decently, even in London." The incident is reported by Richard Newman, who adds that Backhaus eventually moved to Switzerland "in opposition to the Nazi regime" and says his "offensive behavior... may have been due to his awareness of German agents operating in London at the time..."
Recordings
Backhaus had a long career on the concert stage and in the recording studio. He recorded the complete piano sonatas and concertos of Beethoven and many works of Mozart and Brahms, and in 1928 he became the first pianist to record the complete Etudes of Frédéric Chopin. Backhaus' readings are still widely regarded as among the best recordings of those works. His 27 January 1936 recording of Brahms's Waltzes, Op. 39, runs just over thirteen minutes. His recordings of the complete Beethoven sonatas, made in the 1950s and '60s, display exceptional technique for a man in his seventies, as do the two Brahms concertos from about the same time. His live Beethoven recordings are in some ways even better, freer and more vivid. On the other hand, his playing was sometimes accused of being "mechanical" and "lacking in insight." His chamber recordings include Brahms's cello sonatas with Pierre Fournier, and Schubert's Trout Quintet with the International Quartet and Claude Hobday. The Times praised Backhaus in its 1969 obituary for having upheld the classical German music tradition of the Leipzig Conservatory. His phenomenal transposing powers spawned many anecdotes: finding the piano a semitone too low at a rehearsal of Grieg's A minor Concerto, he simply played it in B-flat minor — and then in the original A minor at the concert after the instrument had been correctly tuned. Backhaus was quick to recognize the importance of recordings. His drastically abridged 1909 recording of the Grieg Piano Concerto, lasting about six minutes, was not only the first recording of that work, but also the first recording of any concerto. He recorded it complete, and magnificently, in the early 1930s. At the time of his death, Backhaus had nearly completed his second complete Beethoven sonata cycle. All that was missing was the Hammerklavier Sonata.