- Co-founder of the DNVP
- Member of the Reichstag
- Chair of the DNVP’s parliamentary group
- Chair of the DNVP
Westarp helped found the conservative DNVP party in the fall of 1918. From 1920, he represented the DNVP in the Reichstag. In the early days of the republic, he was a harsh critic of the Weimar democracy and maintained close contact with the conspirators of the Kapp Putsch. After that, he increasingly pushed for the DNVP’s integration into the government. From 1925 to 1929, he was the DNVP’s Reichstag group’s chair and from 1926 to 1928, the party’s chair. Hugenberg was elected party chair in 1928. He wanted the party to strongly oppose the government and tried to thwart Westarp’s plans to support the Brüning cabinet. Together with another member in the top echelons of the DNVP, Gottfried Reinhold Treviranus, Westarp founded the Conservative People’s Party, having left the DNVP in 1930.