Incumbent, Challengers, Open Seats

For next time, Carson & Jacobson ch. 4

From last time:

• Gerrymandering game: cracking and packing
• Partisan opinion depends on who is doing the gerrymander. Note p. 10 on building minority coalitions -- ulterior motive of "bleaching"

Racial Gerrymandering update to p. 17:  the Callais decision

The Incumbency Advantage

Incumbents Usually Win -- House and Senate

House and Senate margins  

The traditional explanations

• Constituency service
• Constituent communications
• Pork "Vote No and Take the Dough

The current explanation?  (hint: p.  36)

Reasons for defeat

• Scandal
• Redistricting
• New territory
• Incumbent v. Incumbent
• Partisan waves favoring the other party (p. 78)
• Primaries

Bailing out ahead of defeat

The 2026 picture

• Primary losses
• Overall

The special case of the GOP under Trump

Members seeking House or Senate renomination whose opponents Trump endorsed

Year	Republican member	Seat contested	Trump-endorsed opponent	Member’s result	Source
2016	George Holding	House, NC-2	Rep. Renee Ellmers	Won primary against fellow incumbent	Roll Call
2018	Mark Sanford	House, SC-1	Katie Arrington	Lost primary	ABC News
2022	David McKinley	House, WV-2	Rep. Alex Mooney	Lost primary against fellow incumbent	Ballotpedia
2022	Rodney Davis	House, IL-15	Rep. Mary Miller	Lost primary against fellow incumbent	Ballotpedia
2022	Nancy Mace	House, SC-1	Katie Arrington	Won primary	Roll Call
2022	Tom Rice	House, SC-7	Russell Fry	Lost primary	Ballotpedia
2022	Peter Meijer	House, MI-3	John Gibbs	Lost primary	Ballotpedia
2022	Jaime Herrera Beutler	House, WA-3	Joe Kent	Lost: failed to advance from top-two primary	Roll Call
2022	Dan Newhouse	House, WA-4	Loren Culp	Survived top-two primary; Culp was eliminated	Roll Call
2022	Liz Cheney	House, Wyoming at-large	Harriet Hageman	Lost primary	PBS/AP
2022	Lisa Murkowski	Senate, Alaska	Kelly Tshibaka	Survived top-four primary; defeated Tshibaka in general election	PBS/AP
2024	Bob Good	House, VA-5	John McGuire	Lost primary; recount confirmed defeat	Roll Call
2024	Dan Newhouse	House, WA-4	Jerrod Sessler and Tiffany Smiley	Survived top-two primary; defeated Sessler in general election	Endorsements; result
2026	Bill Cassidy	Senate, Louisiana	Rep. Julia Letlow	Lost: finished third and missed primary runoff	AP
2026	John Cornyn	Senate, Texas	Ken Paxton	Lost primary runoff	PBS
2026	Thomas Massie	House, KY-4	Ed Gallrein	Lost primary	AP

Recruiting challengers

• Meaning of "quality challenger" has changed (p. 63)
• Rahm recruits Shuler in 2006