Career
He worked as a lawyer first at the Landgericht Mülhausen and then at Alsace-Lorraine"s Supreme Court at Colmar. A Russian national through birth to Russian parents, who had immigrated to France in 1858, he was naturalised as German in 1882. In 1895 he founded the democratic People"s Party of Alsace-Lorraine and became its first president
In the German general election, 1903 he gained the majority of the votes in the Alsace-Lorraine constituency Number.
9 (comprising about the rural district Straßburg-Land, not including the city of Strasbourg proper). In the next elections, he ran in two constituencies simultaneously, in Number.
9 again and in Number. 3 (Colmar), however, in both cases he only came second by votes and also lost the run-offs.
In 1905 Colmar"s city parliament elected him mayor with 15 of 29 votes. After the outbreak of the First World War Blumenthal emigrated to France, where he promoted the reannexation of Alsace-Lorraine to France.
He was condemned to death eight times and had sentences totaling five hundred years prison imposed upon him by the Imperial German government following his escape from Alsace to inform the world of the plight of Alsace and German Lorraine under German rule. He wrote a publication entitled Alsace-Lorraine – a study of the relations of the two provinces to France and to Germany, and a presentation of the just claims of their people, which was published in 1917, by G.P. Putnam"s Sons in 1917.
Blumenthal presented this publication to the United States Congress as means to gain American support for the freeing of Alsace and Lorraine from German rule and its reannexation to France without a plesbiscite of the inhabitants.
The descendants of Daniel Blumenthal now reside in Australia. The rue Daniel Blumenthal in Colmar is named in his honor.