Clerk of the Supreme Court Caswell became the first incumbent for this office to lose his party's nomination in a primary.
Mueller was a resident of St. Cloud and former Stearns County District Court clerk. Mueller was backed by Arthur C. Townley's Nonpartisan League. The League put up its own slate of candidates that controversially challenged several incumbents in primaries this cycle. Mueller's victory prompted many leaders and newspapers to call to the end of the primary system.
Magnuson was a former fire marshall and city clerk in St. Cloud. He was also a Republican candidate for Auditor in 1922, the 6th CD in 1924, for Railroad and Warehouse Commissioner in 1928, and again for Supreme Court Clerk in 1938.