Support for Far-Right Parties

Cordon Sanitaire

Cordon Sanitaire Under Strain in Germany

Public Response in Germany

Cordon Sanitaire Under Strain in Spain

Public Response in Spain

Why We Should Care

Breaks in isolation normalise and strengthen radical-right parties (RRPs) by eroding the stigma that once surrounded them.
(Mudde, 2019; Valentim, 2024)

• Programmatic convergence
• Executive coalitions
• Legislative cooperation

Programmatic Convergence

Can mainstream parties win voters by accommodating RRP positions?

• Can win back anti-immigration voters while repelling pro-immigration voters (Chou et al., 2021; Haas et al., 2023)
• Net effects vary across party camps; mainstream left parties may gain electorally, while the mainstream right might not (Spoon and Klüver, 2021; Hjorth and Larsen, 2022)
• Can increase support for RRPs by heightened issue salience and legitimization of far right discourse (Krause et al., 2023)

Executive Coalitions

What are the consequences of including RRPs in executive office?

• Leads to mainstreaming and policy moderation of RRPs (Axelsen, 2024)
• Can increase support for RRPs, while not affecting support for mainstream parties (Jacobs et al., 2024)
• Effect depends on the party’s position in coalition; RRPs suffer losses when joining as junior partners (Riera and Pastor, 2021)

Legislative Cooperation

What do we know about legislative cooperation?

• Rural districts, in particular, are at the forefront of cooperation (Schroeder et al., 2025)
• Happens where center-right parties are in opposition or lead deologically mixed coalitions (Heinze, 2022)

Local Politics as Laboratories of Norm Defiance

Prior work concentrates on programmatic convergence and executive coalitions at the national level.

• Weaker party cues
• Lower media scrutiny
• More pragmatism, less ideological conflict

The Realities of Local Politicians

“Local politicians must balance ideological principles with harsh financial conditions and political realities, all while being closely connected to the community and the citizens impacted by their decisions.” (Esaiasson & Licht, 2024)

Local Politics as “Managerial Democracies”

• Issue scope: many local problems lack clear ideological valence (Oliver et al., 2012; Peterson, 1981)
• Home style: close geo and social ties lower information asymmetry. Reputation hinges on visible, concrete performance (Fenno, 1978)
• Fiscal constraints: Higher-level budget rules for local-level politics limit room for ideological projects.
  
• Media focus: Local outlets emphasize service failures over abstract ideological debates (Ellger et al., 2024)

Adherence can be Costly

In local councils, where elected officials must routinely deliver public goods, upholding a cordon sanitaire can impose costs:

• Poor local service delivery drives support for RRPs (Dickson et al., 2024)
• RRPS strategically undermine local public goods provision (Wappenhans, 2025)

• Refusing cooperation can stall public goods provision
• Cooperation may improve service delivery but erodes normative boundaries

What does this mean for RRPs electoral outcomes?

Visibility Matters

Magnitude of any electoral response depends on how visible cooperations are. Voters can only react if they are aware of the cooperations.

• High visibility amplifies whichever mechanism dominates
• Low visibility weakens the effect

Case

East-German municipality-level cooperations with the AfD

Data Overview

• Outcomes: vote shares & turnout for municipal elections in 2014 & 2019 (GERDA + 2024 updates) (Heddesheimer et al., 2025)
• Treatment: 24,000 Google‑scraped press items covering cooperations
• Mechanism: 180,000 GPT-4o classified local news articles (party portrayals, issue salience, and cooperation narratives)

What do we mean by “cooperation”?

• Voting Proposal: mainstream councillors back AfD motions or their own pass thanks to AfD swing votes.
• Voting Candidate: mainstream councillors back AfD nominees or candidates win via AfD swing votes.
• Public endorsement: mainstream actors openly welcome cooperation.
• Joint faction: joint factions or electoral lists containing AfD and mainstream members.
• Other: e.g. jointly suspending council session.

How we Detect Cooperations and Visibility

Where Cooperation Happens

How Mainstream Parties Cooperate

What Cooperations are About

Design 1: Two-Period Difference-in-Differences

\[ Y_{it} = \alpha_i + \gamma_t + \tau \bigl(T_i \times \mathbf{1}[t=2024]\bigr) + \varepsilon_{it} \]

• \(Y_{it}\): vote shares/turnout in municipality \(i\) at election year \(t\)
• \(T_i = 1\) if \(i\) experienced local AfD cooperation after 2019 election
• Compare 2019 → 2024 changes in treated vs. controls

Assumption: Parallel trends in the absence of treatment

Design 2: Synthetic Difference-in-Differences

\[ \{\hat{\tau}, \hat{\alpha}_i, \hat{\gamma}_t\} \;=\;\arg\min_{\tau, \alpha_i, \gamma_t} \sum_{i,t} \Bigl(Y_{it} - \alpha_i - \gamma_t - (T_i \times \mathbf{1}[t=2024])\,\tau \Bigr)^2\,\hat{\omega}_i\,\hat{\lambda}_t \]

• Re-weights and matches pre-exposure trends to weaken parallel trend assumption (Arkhangelsky et al., 2021)
  • But: Requires at least 2 pre-treatment periods

→ Design 2 uses all periods, but only 11 treated municipalities

Main Results

AfD-CDU Cooperations only

Testing the Mechanism

1. We scrape 180,000 local news articles that mention the AfD (2019‑24)
2. GPT‑4o coding, using a structured prompt, labelling each article on:
   • Issue topic (18 categories)
   • AfD portrayal (outsider ↔︎ normal)
   • Tone toward AfD (positive / neutral / negative)
   • Mentions of mainstream parties + competence/pragmatism cues
3. Merge with events by mapping local outlets to municipalities using newspaper coverage data

Mechanism Evidence

Conclusion

• Local cooperation with RRPs reduces support in next local election
• Effect strongest for more visible cooperations
• No effects on center-right parties, positive tendency for center-left parties

Normalization Beyond the Ballot Box

Non-electoral effects of normalizing RRPs are well-documented:

• Welfare costs (Funke et al., 2023)
• Eroding buerocratic capacity (Bellodi et al., 2024; Gratton & Lee, 2024)
• Out-group violence (Romarri, 2020; Dancygier, 2023; Riaz et al., 2024; Mueller and Schwarz, 2021, 2023)