In the fall of 1918, the United States was approaching a midterm election like none other before. Not only were President Woodrow Wilson and his fellow Democrats trying to keep control of Congress during the home stretch of World War I—they were trying to do so in the middle of one of the deadliest pandemics in history.

The first wave of the so-called Spanish flu had begun that spring, when the first official cases were reported at Camp Funston, a U.S. Army training camp at Fort Riley, Kansas. The second wave, which emerged in September 1918 at an army training camp and naval facility near Boston, would be far worse. This time, the flu spread quickly into the civilian population of Boston and other cities on the East Coast. In the month of October alone, a total of 195,000 Americans died.

As scientists raced to find a vaccine, public health officials turned to time-tested methods of social distancing and quarantine. State and local officials around the country banned public gatherings, closing schools, churches, theaters, bars and other spots where people typically met in groups.

READ MORE: Pandemics that Changed History

Apic/Getty Images
Red Cross volunteers at work during the 1918 flu pandemic.

Candidates Campaigned Amid Social Distancing

Due to these widespread bans, many candidates in the 1918 midterms could not campaign in the typical way. Barred in many cases from holding rallies or speaking events, they were forced to rely on less direct forms of communication, including seeking out newspaper coverage or sending campaign literature through the mail.

Some candidates even accused public health officials of trying to influence the election by limiting turnout. After local authorities canceled a scheduled speech by Democrat Alfred E. Smith in Haverstraw, New York due to concerns over the flu, another Democratic leader fumed to the New York Times about a “Republican quarantine against Democratic campaign speeches.” (Smith still narrowly managed to unseat the Republican incumbent, Charles Whitman, as governor that November.)

READ MOREHow US Cities Tried to Halt the Spread of the 1918 Spanish Flu

Voting in a Pandemic

Since local and state authorities largely controlled the measures taken to control the spread of the virus, voting in the 1918 midterms looked very different depending on what part of the country you were in.

By November, when the flu was generally waning in the eastern part of the country, it was ramping up in the West. In Sacramento, California, some poll sites couldn’t open, according to the Sacramento Bee, because “there were not enough citizens who were well enough.” In San Francisco, health officials issued an order in late October mandating that people wear face masks while in public or in a group of two or more people. All poll workers and voters were required to wear masks on Election Day, prompting the San Francisco Chronicle to call it “the first masked ballot ever known in the history of America.”

By contrast, things were getting back to normal on the East Coast. Public health officials in Washington, D.C. made the decision to reopen churches on October 31, and schools and theaters on November 4, the day before the midterm election. In New York City, health commissioner Dr. Royal S. Copeland similarly began rolling back restrictions in early November, with businesses resuming their normal operating hours by Election Day.

Despite the risks involved, there appears to have been little public discussion about simply postponing the election that year. Jason Marisam, a law professor at Hamline University who has studied how the flu pandemic affected the 1918 midterms, argues that there might well have been talk of postponement—if the United States hadn’t been at war at the time. But with their troops fighting overseas, Americans’ spirit of civic pride was running high, and voting was seen as a necessary act of patriotism.

READ MORE: Why the Second Wave of the 1918 Spanish Flu Was So Deadly

Low Turnout—and a Republican Victory

Patriotism aside, only around 40 percent of eligible U.S. voters cast their ballots on November 5, 1918, compared with 50 percent in the previous midterm. Republicans won control of both the House and Senate for the first time since 1908, marking a major defeat for Wilson and his foreign policy agenda.

The election’s low turnout can’t be entirely blamed on the flu. Around 2 million men were fighting in the war at the time, representing a high percentage of the U.S. voting population. (American women wouldn’t get the right to vote until 1920.) Yet even if the flu only partially explains the voting drop-off, it undoubtedly had an impact.

“If just a fraction of the drop in turnout from 1914 to 1918 was due to the presence of the flu, then the disease was responsible for hundreds of people not voting,” Marisam writes.

Though the midterm election had managed to go forward in the pandemic, its aftermath saw an increase in flu infections and deaths, likely due to the lifting of quarantine restrictions. Then, six days after Election Day, an armistice ended fighting in World War I. Many Americans left their homes for the first time in weeks or months, gathering in groups to celebrate the war’s end. Tragically, the festivities surrounding the Armistice, and the mass return of soldiers from the front, would lead to a new surge of influenza cases in many cities across the country—and around the world.

The political fallout from the 1918 election was real, too. Republicans in Congress, back in power, then blocked ratification of the Versailles Treaty and U.S. membership in Wilson’s beloved League of Nations. In 1920, Warren G. Harding won the presidency, spelling the end of the Progressive Era and beginning an era of Republican dominance that would last another 12 years.

See all pandemic coverage here.