Strijdom served in the German South West Africa campaign in World War I, as a member of the South African Medical Corps and, later, of Helgaardt's Scouts, where he reached the rank of corporal [REF].
After the National Party of J.B.M. Hertzog[REF] merged with the South African Party of General Jan Smuts[REF] and formed the United Party (UP) during the World Economic Crisis in 1932,[REF] Strijdom was part of the break-away faction of the National Party,[REF] named the Gesuiwerde Nasionale Party (Purified National Party) [REF].