William Boyd Allison was an American politician. An early leader of the Iowa Republican Party, he represented northeastern Iowa in the United States House of Representatives before representing his state in the United States Senate. By the 1890s, Allison had become one of the "big four" key Republicans who largely controlled the Senate, along with Orville H. Platt of Connecticut, John Coit Spooner of Wisconsin and Nelson W. Aldrich of Rhode Island.

Orville Hitchcock Platt was a United States senator from Connecticut. Platt was a prominent conservative Republican and by the 1890s he became one of the "big four" key Republicans who largely controlled the major decisions of the Senate, along with William B. Allison of Iowa, John Coit Spooner of Wisconsin and Nelson W. Aldrich of Rhode Island.