When the United States declared war on Germany in April 1917, President Woodrow Wilson faced a reluctant nation. Wilson had, after all, won his reelection in 1916 with the slogan, “He kept us out of the war.” To convince Americans that going to war in Europe was necessary, Wilson created the Committee on Public Information (CPI), to focus on promoting the war effort.

To head up the committee, Wilson appointed a brilliant political public relations man, George Creel. As head of the CPI, Creel was in charge of censorship as well as flag-waving, but he quickly passed the censor’s job to Postmaster General Albert S. Burleson. The Post Office already had the power to bar materials from the mail and revoke the reduced postage rates given to newspapers and magazines.

Handsome, charismatic, and indefatigable, Creel thought big and out of the box. He disliked the word “propaganda,” which he associated with Germany’s long campaign of disinformation. To him, the CPI’s business was more like advertising, “a vast enterprise in salesmanship” that emphasized the positive. A veteran of Wilson’s two successful presidential campaigns, Creel knew how to organize an army of volunteers, and 150,000 men and women answered his call. The Washington office, which operated on a shoestring, was part government communications bureau and part media conglomerate, with divisions for news, syndicated features, advertising, film, and more. At Wilson’s insistence, the CPI also published the Official Bulletin, the executive-branch equivalent of the Congressional Record.

Creel’s first idea was to distribute good news and disclose as many facts about the war as he could without compromising national security. His M.O. was simple: flood the country with press releases disguised as news stories. Summing up after the war, Creel said he aimed to “weld the people of the United States into one white-hot mass instinct” and give them a “war-will, the will to win.”

During the 20 months of the U.S. involvement in the war, the CPI issued nearly all government announcements and sent out 6,000 press releases written in the straightforward, understated tone of newspaper articles. It also designed and circulated more than 1,500 patriotic advertisements. In addition, Creel distributed uncounted articles by famous authors who had agreed to write for free. At one point, newspapers were receiving six pounds of CPI material a day. Editors eager to avoid trouble with the Post Office and the Justice Department published reams of CPI material verbatim and often ran the patriotic ads for free.

For the first two months, nearly all of the information generated by the CPI consisted of announcements and propaganda of the cheerleading variety: salutes to America’s wartime achievements and American ideals. At Creel’s direction, the CPI celebrated America’s immigrants and fought the perception that those who hailed from Germany, Austria, and Hungary were less American than their neighbors. Creel thought it savvier to try to befriend large ethnic groups than to attack them.

But after two months, Creel and Wilson could see that popular enthusiasm for the war was nowhere near white-hot. So on June 14, 1917, Wilson used the occasion of Flag Day to paint a picture of American soldiers about to carry the Stars and Stripes into battle and die on fields soaked in blood. And for what? he asked. In calling for a declaration of war, he had argued that the world must be made safe for democracy, but with his 1917 Flag Day speech, he trained the country’s sights on a less exalted goal: the destruction of the government of Germany, which was bent on world domination.

After Flag Day, the CPI continued to churn out positive news by the ton, but it also began plastering the country with lurid posters of ape-like German soldiers, some with bloody bayonets, others with bare-breasted young females in their clutches. “Destroy this mad brute,” read one caption. It also funded films with titles like The Kaiser: The Beast of Berlin and The Prussian Curse.

The CPI’s happy news sometimes downplayed the shortcomings of the U.S. war effort, but the demonizing of all Germans played to low instincts. Thousands of self-appointed guardians of patriotism began to harass pacifists, socialists, and German immigrants who were not citizens. And many Americans took CPI’s dark warnings to heart.

Even the most casual expression of doubt about the war could trigger a beating by a mob and the humiliation of being made to kiss the flag in public. Americans who declined to buy Liberty Bonds (issued by the Treasury to finance the war) sometimes awoke to find their homes streaked with yellow paint. Several churches of pacifist sects were set ablaze. Scores of men suspected of disloyalty were tarred and feathered, and a handful were lynched. Most of the violence was carried out in the dark by vigilantes who marched their victims to a spot outside the city limits, where the local police had no jurisdiction. Perpetrators who were apprehended were rarely tried, and those tried were almost never found guilty. Jurors hesitated to convict, afraid that they too would be accused of disloyalty and roughed up.

Both Creel and Wilson privately deplored the vigilantes, but neither acknowledged his role in turning them loose. Less violent but no less regrettable were the actions taken by state and local governments and countless private institutions to fire German aliens, suspend performances of German music, and ban the teaching of German in schools.

In their effort to unify the country, Wilson and Creel deployed their own versions of fake news. While the worst that can be said of the sunny fake news flowing out of the CPI was that it was incomplete, the dark fake news, which painted the enemy as subhuman, let loose a riptide of hatred and emboldened thousands to use patriotism as an excuse for violence.

Patricia O’Toole is the author of five books, including The Moralist: Woodrow Wilson and the World He Made and The Five of Hearts: An Intimate Portrait of Henry Adams and His Friends, which was a finalist for the Pulitzer Prize and the National Book Critics Circle Award_._