after winning the 1925 election, casselman sought re-election in 1926 and again won, this time against progressive candidate preston elliot. casselman went on to be re-elected as mp in the next eight federal elections, taking place in 1930, 1935, 1940, 1945, 1949, 1953, 1957, and 1958. during the 1925, 1926, 1930 and 1935 federal elections casselman represented the conservative party, while in the 1940 election he represented the national government party. during the last five federal elections he ran for, in 1945, 1949, 1953, 1957, and 1958, casselman represented the progressive conservatives.