In January 1887 a coalition of Henry George supporters from the New York City Central Labor Union, the Socialist Labor Party and the Knights of Labor organized the United Labor party. However the ties that bound these disparate groups together, during George's 1886 campaign for mayor, soon began to unravel. For one thing, not every supporter agreed that George's single- tax theory should be the party's primary concern. As Samuel Gompers put it, "the mere taxation of land values cannot settle the questions between capital and labor arising from the wage system and the progress of machiney; and a a Labor Party cannot ignore those questions."
For another, not every ULP supporter trusted the Socialist Labor Party-- in fact when the United Labor party met in convention that August, delegates agreed that membership in the SLP violated the ULP's prohibition of membership in another political party, effectively expelling the socialists from the ULP.
But that action only created another problem: The socialists organized the Progressive Labor party and ran their own slate of candidates in New York City's elections that fall, thereby dooming what little chance either party had of success.