Final answer:
Oklahoma's strongest early twentieth-century party hailed from socialist principles, reflective of the Populist Party, which fought for economic and moral equality, especially affecting farmers and urban workers.
Step-by-step explanation:
Oklahoma had one of the strongest statewide (c) socialist political parties during the early twentieth century. The members of the party often used the principles of socialism to justify their efforts for equality on both moral and economic grounds. The Populists, often referred to as the People's Party, were a significant force in American politics at the turn of the twentieth century, especially in the South as well as the western plains and mountain states. They aimed to challenge the economic difficulties faced by farmers and sought to expand their base by attempting to join with urban workers, thus influencing American political culture.
In Oklahoma, the Populist Party had notable electoral successes. They managed to get many seats in state legislatures, send delegates to Congress, and have Populist governors, although by the Progressive Era many of their ideas were assimilated by the two major parties, Republicans and Democrats.