**Marty Jackley secured the Republican nomination for South Dakota’s at-large House seat in the June 2 primary with 79 percent of the vote against limited opposition, while Nikki Gronli advanced unopposed on the Democratic side.** The open seat—vacated after incumbent Dusty Johnson’s unsuccessful gubernatorial bid—remains in a district with a long Republican hold and consistent double-digit advantages in presidential and congressional voting. Trader pricing on victory margins clusters in the 20-30 percent range, reflecting the state’s partisan baseline, absence of recent competitive polling showing movement, and limited visibility for the Democratic nominee. No major late-cycle developments or cross-party endorsements have altered the established pattern, leaving the outcome sensitive mainly to turnout differentials or unforeseen events in the final weeks before November 3.