Henning became notorious for an article of his that appeared in the June 1922 edition of Konservative Monatsschrift. In the article, 'The Real Face of Rapallo Terror', Henning denounced Walther Rathenau as an "international Jew" who had sullied German honour by not mentioning the murder of envoy Wilhelm Graf von Mirbach-Horff in Moscow during the Treaty of Rapallo negotiations. With Rathenau murdered at around the same time it appeared that rogue elements within the DNVP were endorsing political murder and so, under pressure from Chancellor Joseph Wirth, the DNVP leadership expelled the far rightanti-Semitic wing, including Henning. In response Henning joined with Wulle and von Graefe in establishing the German Völkisch Freedom Party as a rightist splinter group. Henning continued to represent this group in the Reichstag until 1928.