Final answer:
Eugene V. Debs was not an influential Populist leader; he was a socialist and labor movement figure. Populist leaders included Mary Elizabeth Lease, Ignatius Donnelly, and James B. Weaver, the 1892 Populist presidential candidate.
Step-by-step explanation:
The individual among the options who was NOT an influential Populist leader is Eugene V. Debs. Debs was indeed involved in the labor movement and was a key figure in the Pullman Strike, but he was more associated with the Socialist movement rather than the Populist movement.
The Populist, or People's Party, included leaders like Mary Elizabeth Lease, a passionate orator; Ignatius Donnelly, who was a politician and writer; and James B. Weaver, who ran as the Populist presidential candidate in 1892. Debs did not fit into this group as a Populist leader.
Many of the initiatives and concerns of the Populist Party centered around agrarian interests, monetary reforms, and opposition to the gold standard, as encapsulated in William Jennings Bryan's famous "Cross of Gold" speech. However, despite the movement's wide appeal, leaders like Debs were ultimately perceived by some as too radical, and he was more recognized for his role in labor rights and the forming of the Socialist Party.