Entryism

Working inside a larger host party to capture or redirect it, rather than building a rival party.

Definition

A radical group joins an established party, uses its ballot line and infrastructure, and pulls it toward the group’s program. The canonical case cited in the corpus: Militant Tendency inside the British Labour Party (early 1980s) — captured Liverpool City Council and three parliamentary seats before expulsion for being “a party within a party.” The term is the analytical core of the right’s DSA narrative; notably, the DSA’s own framing partially embraces the mechanics: Romer endorses the Jacobin “Blueprint for a New Party” line about using the Democratic ballot line as “the electoral equivalent of guerrilla insurgency.”

Key Properties

• Contested application: critics say concealment is essential to DSA entryism; DSA leadership operates openly and rejects the deception charge (implicitly — direct response is a data gap).
• The Militant analogy’s punchline in the hostile source: a DSA member suggested Mamdani’s team study the Marxist-led Liverpool council as a model.
• Watch for: whether Democratic leadership attempts a Kinnock-style expulsion response — no source on this yet.

Examples from Sources

Related

Concepts: democratic-centralism, Democratic Socialism Entities: Democratic Socialists of America (DSA), Red Star Caucus, Democratic Party Debates: Is the DSA taking over the Democratic Party?