As a member of the crew on the Battlecruiser SMS Seydlitz he organised (illegal) revolutionary groups and distributed anti-war literature.
A few days later he led a delegation of the Kiel sailors south to Munich where he was elected a member of the Soldiers' and Workers' Council.
[1][2] During this period Sandtner became a member of the leadership of the Spartacus League, which over the final days of 1918 was reconfigured, renamed and relaunched, now the core of the new Communist Party of Germany.
However, the government was keen not to encourage political extremists unnecessarily: many of those involved in the Munich insurrection received amnesties: Sandtner was released at the end of 1919.
[4] The political backdrop changed with the Nazi take-over in January 1933 and lost no time in transforming Germany into a one-party dictatorship.
Augustin Sandtner spent the first part of 1933 in the border regions of Silesia organising joint rallies by Germany, Polish and Czechoslovakian workers opposed to fascism and the looming risks of war.
[1][2] On 7 February 1933 Sandtner was one of the participants at the "illegal" Sporthaus Ziegenhals meeting, celebrated subsequently (especially during the "East German" years) as the last meeting held by the German Communist Party leadership before the participants were arrested and killed, or in a few cases managed to flee abroad.
After more than eleven years in detention, and still at Sachsenhausen, August Sandtner was one of 24 German camp inmates deemed culpable of "illegal activities" taken out, together with three French antifascists, and shot dead by Nazi paramilitaries (SS) on 11 October 1944.