Hunch. On 30 October The Observer called the race a toss-up, even though Salazar won by almost 21 points in 2024.
The winning margin market resolves on the same certified results: YES if the winner is less than 10 points ahead of the runner-up, counted on the votes for the two main candidates, NO at 10 points or more. A recount moves the date to the day of certification, and BBC News and The Guardian are the backups.
We looked for cases where a House member from the president's party ran again in a midterm after breaking in public with the president on an issue that hurt voters at home, in a district and state the president had won by 10 points or more. The newest group that fits all of this is ten races in 2014, and older years have more. Each was a Democrat who voted on 15 November 2013 for a bill to let people keep their health plans, against Barack Obama's veto threat. (US House Clerk; The American Presidency Project; The Guardian)