Democrat Catelin Drey captured Iowa’s Senate District 1 on Tuesday, winning 55% of the vote against Republican Christopher Prosch’s 45%, according to unofficial results from the Woodbury County auditor. The western Iowa district, centered on Sioux City, backed Donald Trump by 11.5 percentage points in the 2024 presidential election. Drey’s victory flips a Republican-held seat and reduces the GOP’s margin in the 50-member chamber to 33–17, ending the two-thirds supermajority the party secured in 2022. Without that cushion, Republicans will need at least one Democratic vote to confirm Governor Kim Reynolds’ appointments and to advance other measures requiring a supermajority. The special election was called after Republican Senator Rocky De Witt died of pancreatic cancer in June. National and state party committees poured money and volunteers into the race, underscoring growing competition in districts that had lately favored Republicans. Drey will serve the remainder of De Witt’s term, which runs through January 2027.