[4] He received his doctorate in 1900 and returned to Braunschweig as a referendary (trainee lawyer), setting up his own legal practice in 1902.
The ban on SPD participation in elections had been lifted in 1890, but the party was not, at this stage, considered mainstream by members of the political class: Jasper's decision to join it in 1902 was an unusual one for a man from his background.
[6] In July 1915 he went off to serve in the war, having risen to the rank of a Vizefeldwebel (junior officer) by the time he arrived home from the front on 11 November 1918.
Jasper took a lead in the political fight against Sepp Oerter and the workers' council, which he condemned as the "dictatorship of an undemocratic minority".
[5] In April 1919 the Workers' General Strike was ended in Braunschweig which was briefly occupied by a Freikorps unit under the command of General Maercker, after which a level of political stability was restored and Jasper served for several years as president of the Regional Legislature.
His period as minister-president ended for the last time with the regional elections of 14 September 1930, which resulted in a regional government for the Free State of Braunschweig led by the so-called Citizens' Unity List ("Bürgerliche Einheitsliste" / BEL), a coalition of right wing parties which together had amassed 11 seats.
The new regional government now set about purging the educational and cultural departments of Social Democrat elements.
[5] Even before the Nazi party took power nationally at the beginning of 1933, Heinrich Jasper found himself on the receiving end of persecution from the new minister-president, the Nazi party member Dietrich Klagges, who was both his successor and his political opponent in the Braunschweig Legislature.
For Jasper personally, long recognised as the leader of the Braunschweig Social Democrats, and according to one source "one of the people most hated by the Nazis" locally, the backdrop was particularly dire.
[10] On 9 March 1933, the Nazi party's quasi-military wing (SS) took over the "House of the Friends of the People" ("Volksfreund-Haus") which was a substantial building, built for and owned by the SPD, in the city.
On 17 March 1933, the Braunschweig SPD party leadership met in the "Hotel Monopol" in order to discuss the situation and what to do next.
On his arrest he was transferred to Hallendorf Work Education Camp ("Camp/Lager 21"); a forced labour facility on the edge of Salzgitter-Watenstedt.
During the early part of 1945, and with the Red army approaching, preparations were made to close down this institution.