The open-seat contest in South Carolina’s 1st District, following Republican Nancy Mace’s retirement, has produced a tight race driven by the district’s modest Republican lean offset by strong Democratic fundraising and candidate appeal. Nancy Lacore’s substantial cash advantage has funded television ads in the Lowcountry, while Jenny Costa Honeycutt benefits from local council experience, Trump-aligned outside spending, and structural GOP advantages in a seat with R+6 partisan voting index. Recent forecaster shifts into Lean Republican territory reflect these fundamentals, yet multiple polls show margins under 3 points. Final-week turnout among coastal voters, continued ad volume on issues such as flood protection and cost of living, or late shifts in polling averages could widen the gap before November 3.