During the summer of 1923, President Warren G. Harding and First Lady Florence Harding did what many do during the warmer months: They decided to take a road trip. The couple, along with a presidential entourage, embarked upon a journey they called the "Voyage of Understanding," a cross-country speaking tour that included stops in Alaska. Though much of the trip went well, by the end of the summer, Harding would end up dead and his wife's reputation under attack.

There were signs that something was amiss with the 29th U.S. president early in the trip. He tried to play golf on July 26, but was so tired he could only manage a couple of holes. He fumbled during a speech the following day, mistakenly calling Alaska "Nebraska" and clutching the podium for balance. He became ill later that night, which his doctors blamed on spoiled seafood.

And on August 2, 1923, the 57-year-old president died suddenly at the Palace Hotel in San Francisco. Doctors declared a stroke the cause of death, and, per his wife’s wishes, he was embalmed just an hour later. The rush to embalm, combined with Florence's refusal to allow an autopsy or even a death mask, raised more than a few eyebrows. She engaged in more suspicious behavior after his death, when she systematically went through Warren's papers and destroyed a wealth of files and correspondence.

After the funeral was over, Florence was said to remark to friend Evalyn McLean, "Now that it is all over, I am beginning to think it was for the best."

In 1930, former F.B.I. agent Gaston Means wrote a book that accused Florence of offing her husband. It wasn't accidental food poisoning that had made Harding sick a few days before his death, he argued—it was Florence's ambition. Unlike other First Ladies of the era, Florence was deeply involved with her husband’s presidency and once told the press, "I have only one real hobby—my husband."

Her vested interest in Warren's legacy lends a bit of credence to the "motive" Means alleged Florence had—his reputation. Killing off her husband, Means suggests, was the only way to protect his name. Florence was worried that Warren's affairs—including one that resulted in a child—were going to tarnish his legacy, one that was already sullied by the Teapot Dome bribery scandal and other controversies that happened during his administration.

Means’ ghostwriter later admitted that the book had been largely fabricated, but the damage had been done. The public already believed that Harding's sudden death was suspicious; Means' book had simply added fuel to the fire. And Florence wasn't around to refute the accusations. She died in 1924, a little over a year after Warren's untimely demise.

But if there was no foul play afoot, why deny an autopsy? According to the National First Ladies’ Library, Florence may have been trying to protect the reputation of her husband’s doctors. Dr. Sawyer, in particular, is thought to have given Harding some stimulants that may have helped induce the president’s fatal heart attack on August 2. Rather than drag Sawyer’s name through the mud—and perhaps bring her own judgment into question—Florence could have opted to simply close the book on the whole thing.

If that truly was her goal, however, denying the autopsy may have done more harm than good. Dr. Ray Lyman Wilbur was present the night of Harding’s death and later recalled how the public immediately blamed the doctors for his untimely demise. “We were accused of starving the President to death, of feeding him to death, of assisting in slowly poisoning him, and of plying him to death with pills and purgatives. We were accused of being abysmally ignorant, stupid and incompetent, and even of malpractice,” he wrote in his memoirs.

Unlike fellow possible poison victim Zachary Taylor, Harding's body has never been exhumed and tested for poison—but modern-day doctors believe Harding suffered a heart attack.