It started in 1905 in Marion, Ohio, when Harding was the editor of the local newspaper, the Marion Star, and Carrie was married to his friend Jim Phillips, who ran a dry goods store. It continued as Harding campaigned for and served as a U.S. senator and, eventually, ran for president. Through it all, Harding wrote love letters to Carrie, long missives filled with moony sentiment, erotic longing and sometimes despair.
Five years into the affair, Carrie began collecting the letters, some of them 40 pages long and some written on U.S. Senate stationery. The 900 pages in her trove revealed a torrid affair but also tracked tumultuous and tragic world events as the European powers drifted toward war.
Because of an intense whispering campaign in Marion, Carrie took her only child, a daughter named Isabelle, to Berlin in September 1911 for schooling. Twice during her stay in Berlin, she traveled back to the United States to meet secretly with Harding. In 1911, the couple made their way to Montreal for several days of reverie until Carrie returned to Germany. They repeated a transatlantic rendezvous at the end of 1912, this time Carrie traveling on the RMS Mauretania, a sister ship of the famous Lusitania.
By 1913, the relationship was in crisis. Carrie let it be known she was seeing another man in Europe, and Harding concluded he had lost her for good. He decided to run for the Senate in 1914.
When war broke out in Europe in the summer of 1914, Carrie and Isabelle fled Berlin and returned to Marion. That fall, Harding won the election by a handsome margin and was instantly talked about as a leading candidate for president, in large part because he was from Ohio, the birthplace of so many presidents following the Civil War.
Teddy Roosevelt, however, seemed like the prohibitive favorite for the Republican nomination after he made amends within the party following his damaging split to form the Bull Moose Party. And then TR died unexpectedly in January 1919. Suddenly, Harding had a real chance to win the presidency.
By this time, Harding had two major problems. Carrie and Isabelle had returned from Berlin smitten with all things German, and they sided with Germany in the war. It did not take long for agents of the Bureau of Investigation and members of the citizen-police organization known as the American Protective League to begin following Carrie and Isabelle as suspected German spies.