A union leader recently announced he was leaving the Democratic Party. His stated reason was blunt: The party, increasingly influenced by the Democratic Socialists of America and aligned activist networks, is no longer primarily focused on working people. It has been captured by anti-capitalist ideologues and factions whose priorities are ideological transformation and foreign policy alignments rather than the material interests of the union rank and file. 

This moment is not an isolated defection. It is the predictable result of a coalition strategy that prioritized short-term mobilization against a common enemy over long-term coherence with its core constituencies.