Amanda McKinney secured the Republican nomination in Washington’s 4th Congressional District after winning the August 2026 top-two primary with 35% of the vote in the open seat race to succeed retiring Rep. Dan Newhouse. Her Trump endorsement, strong fundraising edge, and backing from aligned super PACs helped consolidate conservative support in a district that leans heavily Republican, where the party has held the seat for over a decade. Democrat John Duresky advanced as the sole major opponent from his party but trails significantly in a constituency that favored Republicans by wide margins in recent cycles. Traders assign McKinney a 92% implied probability of victory ahead of the November 3 general election, reflecting the district’s partisan baseline and primary consolidation. Late developments such as the September 30 debate or unexpected turnout shifts remain the primary variables that could still alter the outcome.