His political career peaked and crashed in the late 1940s when he found himself on the losing side as the newly established German Democratic Republic reverted to one-party government.
During the early post-war period the DVP initially rejected the Weimar Constitution which, as matters later turned out, would form the basis for government in Germany till 1933.
In 1919 Arthur Lieutenant switched his party allegiance to the DDP which was proving less grudging in its acceptance of the post-imperial constitutional structure being put in place.
[2] Regime change took place in January 1933 when the NSDAP (Nazi Party) took power and lost little time in implementing a retreat from democracy in favour of one-party government across Germany.
Following frontier changes mandated by the military winners and large scale ethnic cleansing, there was no future for a German in the now Polish town of Głogów.
This gave rise to acute tensions within the LDPD between those seeking to retain power and influence by dancing to the tune of the SED and those still believing that there was a future for an independent liberal party in (East) Germany.
[4] Külz had not even turned up for the meeting and it was left to his dapper lawyerly deputy,[3] Arthur Lieutenant, to spell out the obvious conclusion that under the circumstances further co-operation across the four occupation zones was from now on, for the eastern Liberals, impossible.
Lieutenant accompanied the housekeeper into Külz's bedroom only to discover that the elderly "east German" Liberal Party leader had unexpectedly died in the night, apparently as the result of a heart attack.
[1] In 1948/49 he was also nominated to membership of the " Provisional Volkskammer"[2] which with the formal founding of the German Democratic Republic in October 1949 would become the new country's National Legislature (always subject to the Leading Role of The Party).