Was splitting the Dakota territory into two states part of a Republican push to build an electoral advantage?
In the 1888 election, Republicans won control of the presidency and both houses of Congress (they lost the popular presidential vote). Throughout the 1880s they had pressed for statehood in the northern tier of territories stretching to the Pacific, expecting enduring gains in the Senate and the Electoral College from their Republican-leaning residents. Before leaving office in early 1889, Democratic president Grover Cleveland yielded, signing legislation dividing the Territory of Dakota into two and paving the way to statehood for both the north and the south, as well as two additional states.
Under his successor, Benjamin Harrison, North and South Dakota became the 39th and 40th states. Republicans picked up all four new Senate seats, as well as seats in nearby states. During Harrison's single term the U.S. added six new states, five of which remain Republican strongholds.