Despite this episode, in February 1931 Hugenberg joined the Nazi Party in booting the DNVP out of the Reichstag altogether, as a protest against the Brüning government. By then, the two parties were in a very loose federation, known as the 'National Opposition'. This was followed in July of the same year by the release of a joint statement, with Hitler guaranteeing that the pair would co-operate for the overthrow of the Weimar 'system'. The two presented a united front at Bad Harzburg on 21 October 1931, as part of a wider right-wing rally leading to suggestions that a Harzburg Front involving the two parties and the veterans' organisation "Der Stahlhelm" had emerged. The two leaders soon clashed, and Hugenberg's refusal to endorse Hitler in the 1932 German presidential election widened the gap. Indeed, the rift between the two opened further when Hugenberg, fearing that Hitler might win the Presidency, persuaded Theodor Duesterberg to run as a Junker candidate after Prince Oskar of Prussia declinced to run as the DNVP candiate. Although Duesterberg was eliminated on the first vote, due largely to Nazi allegations regarding his Jewish parentage, Hitler nonetheless failed to secure the Presidency.