Kurt von Schleicher
Kurt von Schleicher (1882-1934) was the last non-Nazi Chancellor of the Weimar Republic, who rose to prominence in the Army and, with the patronage of Oskar von Hindenburg, son of President Paul von Hindenburg, became politically influential. Another patron was General Wilhelm Groener, Erich Ludendorff's successor as First Quartermaster General, the operational Army Chief of Staff, whose wartime adjutant he had been. In his political dealings, he made many alliances, but was not an advocate of democracy.
In the First World War, he had brief combat service and primarily was on the staff. After the war, he continued, under Gen. Hans von Seeckt, to organize the secret rearmament of Germany in the Black Reichswehr; he was a negotiator with the Soviet Union in obtaining training. William Shirer called him a "gifted manipulator witha passion for intrigue, [who] worked best under cover in the dark.
When Groener became Weimar Minister of Defense in 1928, he put von Schleicher into a new office called the Ministry Bureau (Ministeramt), which dealt with Army relations to the ministries and the politicians. Using that influence, he worked to oust Werner von Blomberg from a senior post. Groener and Schleicher, in 1929, took action against young officers that had suggested cooperation with the Nazi "national revolution". They opposed radicalism in the army and wanted political discipline, treating the Nazis as one more paramilitary group like the Freikorps in the early twenties. They made the mistake, however, of assuming that Heinrich Bruening would be a chancellor who would support these reforms, even though Bruening was a monarchist. 
By 1930, his concept of strong government led him to encourage Heinrich Bruening, as chancellor, to rule by decree. When Bruening did not do well, he contacted Ernst Roehm and Gregor Strasser, and started negotiating with the Nazis.
The last pre-Nazi governments
After the April 1932 elections, Groener and Bruening obtained a Cabinet decree banning the Sturmabteilung (SA) and Schutzstaffel, but they were surprised to get a strong negative reaction from the Army. Schleicher convinced Hindenburg that banning the SA was detrimental to the Reichswehr, and the decree about the SA was quickly revoked. Groener resigned on 11 May, and Schleicher became Minister of Defense in his place.  Bruening lasted only a bit longer, to 30 May, and Franz von Papen, thought to be sympathetic to the Army, appointed the new Chancellor. Papen and Schleicher recognized the government needed mass support, and offered, to lift the ban on the SA, in order to "tame" the Nazis in the July 1932 elections. 
- William Shirer (1960), Rise and Fall of the Third Reich, Simon & Schuster, p. 150
- Richard J. Evans (2003), The Coming of the Third Reich, Penguin, ISBN 1-59420-004-1, pp. 248-250
- Max Domarus, ed. (1992), Hitler: Speeches and Proclamations, 1932-1945, vol. The years 1935 to 1938, Bolchazy-Carducci Publishers, p. 1276
- Evans, pp. 283-285