Klara Auerbach / The Atlantic

Today, the House Committee on Oversight and Reform is scheduled to hold the first hearing in a quarter century on whether to admit the District of Columbia as a state. Over the past year, Puerto Rico’s tribulations after a deadly hurricane have invigorated the statehood movement there, too. Adding the 51st and 52nd stars to the flag might seem like a dramatic change to Americans who haven’t seen a new one in nearly six decades—and Republicans have been quick to characterize the very notion as a radical move. In June, Senate Majority Leader Mitch McConnell warned that a House plan to admit the two jurisdictions to the union would give the Democrats four more senators, permitting them to impose “full-bore socialism” on America, and he pledged to stop it.

The number of states in the union has been fixed at 50 for so long, few Americans realize that throughout most of our history, the addition of new states from time to time was a normal part of political life. New states were supposed to join the union when they reached a certain population, but in the late 19th century, population mattered a great deal less than partisanship. While McConnell is right to suspect that admitting Puerto Rico and the District of Columbia now would shift the balance in Congress toward the Democrats, the Republican Party has historically taken far more effective advantage of the addition of new states.

In 1889 and 1890, Congress added North Dakota, South Dakota, Montana, Washington, Idaho, and Wyoming—the largest admission of states since the original 13. This addition of 12 new senators and 18 new electors to the Electoral College was a deliberate strategy of late-19th-century Republicans to stay in power after their swing toward Big Business cost them a popular majority. The strategy paid dividends deep into the future; indeed, the admission of so many rural states back then helps to explain GOP control of the Senate today, 130 years later.

During the Civil War, the United States government had organized new territories in the West at a cracking pace, both to keep the Confederacy at bay and to bring the region’s mines and farmland under government control. The territories produced silver and gold, but didn’t attract the flood of settlers that would force immediate statehood, as the California gold strikes did in 1850. The war created a labor shortage, and there was work enough back East to give migrants pause before challenging the Apache, Comanche, Lakota, and Cheyenne, who controlled the West. Congress admitted Nevada in 1864, but by the end of the decade, the addition of new states had stalled. Then, after the 1870 readmission of Georgia, the last of the Confederate states, the drive to organize the West became entangled in the desperate struggle between Republicans and Democrats to control the nation.

The admission of Colorado, in 1876, showed the way. In the 1874 midterm elections, Republicans lost control of the House of Representatives for the first time since the Civil War. Just before Democrats took over, Congress struck a tentative agreement to admit two new states, Colorado and New Mexico, both controlled by Republican machines. Colorado had slightly fewer than 40,000 people in 1870, and New Mexico had more than 90,000. In March 1875, Congress let statehood for Colorado go forward before the upcoming election, but the admission of New Mexico stalled. A coalition of Democrats joined with eastern Republicans, who howled, according to an 1876 New York Times article, that New Mexico was inhabited by “ignorant, priest-ridden ‘Greasers’”—a slur for people of Mexican origin—and should not be given “the right to send two Senators to vote equally with those of New-York, Pennsylvania, and other great States of the Union.”

Colorado’s admission was momentous. In the 1876 election, the Republican Rutherford B. Hayes lost the popular vote, but the new state’s three electoral votes kept his candidacy alive long enough for a Republican-dominated temporary electoral commission to award him the presidency in one of the most hotly contested presidential elections in the nation’s history.

The Republicans had won every presidential election from 1860 to 1876, and controlled both houses of Congress for all but two years of that period, but their governing majority was evaporating. In 1880, after a major Democratic scandal, the Republican James A. Garfield won election by only slightly more than 8,000 votes out of almost 10 million cast, and in 1884, a Democrat, New York’s Grover Cleveland, won the presidency. For Republicans, Cleveland’s election signaled the apocalypse. They had come to believe that the key to American prosperity was the Republican tariff system, which protected American business. Democrats, in contrast, complained that tariffs drove up the price of consumer goods and enabled industrialists to collude to raise prices. Cleveland won by promising to reduce tariff rates. Worse for Republicans, the South had gone solidly Democratic after 1876, and by the time of Cleveland’s victory it was clear it would remain so for the foreseeable future. Not for the last time, Republicans protested that the nation was falling to socialism.

So they changed the political equation. Vowing to regain the White House, Republican leaders first flooded the country with pro-business literature, and then chose the nondescript Ohio Senator Benjamin Harrison, who would toe the line on the tariff, as their nominee for president. Next they tapped a Philadelphia department-store entrepreneur, John Wanamaker, to persuade wealthy industrialists to invest in the Republican war chest, constructing a modern system of campaign finance. Their advertisements and threats that Democrats would destroy the economy enabled Republicans to win control of Congress. Harrison lost the popular vote by about 100,000 votes, but he won the election in the Electoral College. (When Harrison piously declared that “Providence has given us this victory,” his campaign manager scoffed that “Providence hadn’t a damn thing to do with it. [A] number of men were compelled to approach the penitentiary to make him President.”)

In the face of an emerging Democratic majority, Republicans set out to cement their power. The parties had scuffled for years over admission of new states, with Democrats now demanding New Mexico and Montana, and Republicans hoping for Washington and Dakota (which had not yet been divided in two). Before the election, Congress had discussed bringing in all four states together, but as soon as the Republican victory was clear, Democrats realized they had to get the best deal they could or Republicans would simply admit the Republican states and ignore the Democratic ones, as they had done in 1876. So on February 22, 1889, outgoing President Cleveland signed an act dividing the Dakota Territory in half, and permitting the two new territories, along with Montana and Washington, to write constitutions before admission to the union the following year. They passed over New Mexico, which had twice the population of any of the proposed states.

Republicans did not hide their intentions. In the popular Frank Leslie’s Illustrated Newspaper, President Harrison’s son crowed that the Republicans would win all the new states and gain eight more senators, while the states’ new electors meant that Cleveland’s New York would no longer dominate the Electoral College. When the Republicans’ popularity continued to fall nationally, in 1890 Congress added Wyoming and Idaho—whose populations in 1880 were fewer than 21,000 and 33,000 respectively—organizing them so quickly that they bypassed normal procedures and permitted volunteers instead of elected delegates to write Idaho’s constitution.

Democrats objected that Wyoming and Idaho would have four senators and two representatives even though there were fewer people in both together than in some of Massachusetts’s congressional districts, but Harrison’s men insisted that they were statesmen rather than partisans. They accused Democrats of refusing to admit any states that did not support their party—a reversal of the actual record—and claimed Republicans supported “the prosperous and growing communities of the great West.” But moderate Republicans sided with the Democrats, pointing out that the Harrison administration had badly undercut the political power of voters from populous regions, attacking America’s fundamental principle of equal representation.

Harrison’s men didn’t care. “The difference between the parties is as the difference between the light and darkness, day and night,” one supporter argued in Frank Leslie’s. The Republican Party, he insisted, must stay in power to protect Big Business. If that meant shutting more populous territories out of statehood and admitting a few underpopulated western states to enable a minority to exercise political control over the majority of Americans, so be it. Today, the District of Columbia has more residents than at least two other states; Puerto Rico has more than 20. With numbers like that, admitting either or both to the union is less a political power play on the Democrats’ part than the late-19th-century partisan move that still warps American politics.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.