Otto Braun
In multiple legal cases, he defended Social Democrats against various politically motivated charges. High-profile cases that made him known throughout the country included the so-called "Königsberger Geheimbundprozeß" in 1904, in which he achieved acquittals for several politicians including the later Minister President of Prussia, Otto Braun. In 1907, Haase was counsel for Karl Liebknecht (SPD) who had been charged with high treason for publishing his screed "Militarismus und Antimilitarismus".