Career
He was part of a wider campaign against German Jews that became a central feature of nationalist politics in Imperial Germany in the late nineteenth century. He came to the fore in 1880 when he was central to the organisation of a petition calling for the removal of the Jews from all public positions. The petition attracted as many as 225,000 signatories.
Joining with Bernhard Förster, the brother-in-law of Friedrich Nietzsche, he set up the Deutscher Volksverein (German People"s League) in 1881 to support the anti-Semitic agenda.
The group struggled for support as it focused on a single issue that spawned a number of movements at the time and it declined further when Förster left for Paraguay in 1886 to set up his ill-fated Nueva Germania project Active co-operation had actually started at the 1890 election when a joint list captured five seats in the The two leaders however often found themselves in disagreement as Liebermann von Sonnenberg was basically a conservative whilst Böckel held a more radical world-view beyond his anti-Semitism, including a desire for land reform.
Liebermann von Sonnenberg also undertook anti-Semitic lecture tours although in 1892 he was forced to abandon one such tour after his credibility suffered a blow at the hands of Rabbi Benno Jacob. Delivering a two and a half hour lecture on the Talmud he was confronted at its conclusion by Jacob, bearing a copy of the Talmud and demanding Liebermann von Sonnenberg read out the passages he had referred to in his lecture.
When Liebermann von Sonnenberg admitted that he could not read even a letter of the Hebrew language, Jacob chided him for speaking about a book which he could not even read and delivered an impromptu lecture of his own refuting the arguments previously advanced.
After this pattern was repeated a few more times Liebermann von Sonnenberg was forced to cancel his tour. Liebermann von Sonnenberg was one of the candidates elected and he soon became noted for his attempts to introduce a bill to ban all Jewish immigration during every session of the His 1897 bill that sought to reintroduce denominational oaths in court cases was passed and represented the only occasion when a bill introduced by one of the anti-Semites was successful. He continued to represent his constituency of Fritzlar until his death in 1911.