Juul Labs this week revealed a novel approach to keeping its e-cigarettes away from underage consumers — the company’s new vaping equipment won’t unlock for anyone under age 21.

The federal government and 39 states are investigating e-cigarette marketing practices, reflecting growing concern about the dangers of vaping and nicotine addiction, particularly among young people. But more than a century ago, the U.S. government was actively pushing tobacco, not protecting citizens from addiction.

How did the U.S. government help cigarettes become one of the biggest winners of World War I? Here is the too-often overlooked history.

The U.S. pushed cigarettes on its troops

As I explore in my new book, “Killer High: A History of War in Six Drugs,” cigarette smoking among civilians and soldiers spiked during the war years. Assistant War Secretary Benedict Crowell estimated that virtually all of the American Expeditionary Forces during the war used tobacco, with cigarettes the overwhelmingly favorite mode of ingestion. And soldiers brought their habit home with them.

This happened as a direct result of a government campaign to promote cigarettes in the name of supporting the troops during the war. This effort boosted tobacco companies, encouraged nonprofits to donate cigarettes and won over a skeptical public that had just a few years earlier been increasingly hostile toward cigarettes.

During the Spanish-American War, military leaders had discouraged cigarette smoking. In World War I, however, military officials encouraged wartime cigarette smoking to sustain morale and discipline, calm nerves, boost alertness, foster camaraderie and suppress hunger.

Cigarettes became so important to soldier maintenance that U.S. Army Gen. John Pershing exclaimed, “You ask me what we need to win this war. I answer tobacco as much as bullets. Tobacco is as indispensable as the daily ration; we must have thousands of tons without delay.”

Maj. Grayson M.P. Murphy claimed that “a cigarette may make the difference between a hero and a shirker,” and that “in an hour of stress a smoke will uplift a man to prodigies of valor; the lack of it will sap his spirit.” The Army’s chief medical officer, William Gorgas, argued that the utility of tobacco in promoting “contentment and morale” trumped any health concerns and urged an antismoking group to not oppose tobacco use by the troops.

The U.S. government soon became the world’s biggest buyer of cigarettes

Soldiers mostly wanted cigarettes — not chewing tobacco or pipe tobacco. Cigarettes were added to the rations for deployed soldiers and cigarette sales to soldiers were also subsidized at base stores and canteens. During the course of the war, the government sent an average of 425 million cigarettes per month to its soldiers on the front lines in France. All in all, it ended up sending approximately 5.5 billion cigarettes abroad.

Soldiers smoked 60 to 70 percent more cigarettes every day, on average, than civilians. This wasn’t just because of nicotine addiction: As historian Cassandra Tate documents in detail in “Cigarette Wars: The Triumph of ‘the Little White Slaver,’ ”cigarettes came to possess enormous cultural value.

Soldiers especially valued smoking as a show of camaraderie. And smoking was a potent antidote to boredom. One volunteer for the Ambulance Corps wrote to his mother back home: “For every hour of activity there are many more when there is nothing to do but wait at one’s post — and these hours of waiting are unspeakably gummy. Here is the chief explanation of why soldiers smoke so much.”

People supported the troops — with cigarettes

Anti-cigarette activists and temperance groups had socially scorned cigarettes before World War I. Eight states had banned the sale of cigarettes, and at least 20 other states were considering passing new anti-cigarette laws. But many of these measures were later abandoned — under wartime conditions, smoking cigarettes was promoted as a lesser evil than other soldierly vices like drinking and paying for sex.

Cigarettes were considered so crucial to the war effort that citizens, charities and organizations such as the Young Men’s Christian Association (YMCA), the Salvation Army and the Red Cross collected both cigarettes and monetary donations to provide the soldiers with cigarettes.

President Woodrow Wilson enthusiastically supported special drives such as the “Smokes for Soldiers Fund,” and these efforts enjoyed exemptions from tobacco taxes and export restrictions. YMCA magazines that once had published antismoking articles began featuring photographs of YMCA volunteers passing out cigarettes to wounded soldiers, with one such image captioned: “Just What the Doctor Ordered.”

The American public became less worried about the risks of smoking, when compared with the horrors of war. A 1914 commentator in the Lancet medical journal said: “We may surely brush aside much prejudice against the use of tobacco when we consider what a source of comfort it is to the sailor and soldier engaged in a nerve-racking campaign … tobacco must be a real solace and joy when he can find time for this well-earned indulgence.”

Civilians also started smoking more

Though the government considered rationing tobacco at home to ensure supplies for the troops, the head of the War Industries Board maintained that cigarettes were just as critical to civilian morale. The government asked the tobacco industry to increase production to keep up with demand from both soldiers and civilians, and producers were more than happy to comply.

Cigarette production tripled during the war years. By capitalizing on patriotic support for American soldiers in their advertisements and public messaging, the cigarette companies were able to overcome the earlier wave of anti-cigarette sentiment in the country.

Wartime exports of American cigarettes skyrocketed, quadrupling from approximately 2.5 billion cigarettes in fiscal year 1914 to more than 9 billion in 1918. Per capita cigarette consumption jumped from 134 per year to 310. Most factories had to run overtime to keep up.

It would not be until decades later and the mass spread of nicotine addiction that the government would embrace tobacco regulation. But by that time most Americans had long forgotten that the government had once been one of the drug’s biggest promoters.

Peter Andreas is the John Hay Professor of International Studies at Brown University. This article is adapted from his new book, “Killer High: A History of War in Six Drugs” (Oxford University Press, 2020).