Black Trump Card
Though heavily utilized by postwar Radical Republicans in order to maintain political power in the South at all costs, black bloc-voting had raised concerns in New York in the 1820’s. In that case, New York’s legislature raised the property-owning minimum to effectively disenfranchise black voters.
Bernhard Thuersam, Director
Cape Fear Historical Institute  
Black Trump Card:
“For…whites determined to hold on to power or to challenge it, the rump African-American vote remained a temptation and, not infrequently, a trump card. “The greatest danger that threatens Democratic [party] supremacy in the South,” a leading white newspaper warned in 1883, “is that the “out” faction always gravitates toward the Negro and secures his aid to rout the “ins.”  With the economic downturn beginning in the late 1880’s, this situation had become volatile, with hardscrabble white people mobilizing behind Populist candidates and formerly quiescent black people awakening to their new balance-of-power opportunities.”
(WEB DuBois, 1868-1919, David L. Lewis, Henry Holt & Company, 1993, page 260)