President James Garfield’s Mistake: Denying lawyer Charles Guiteau a diplomatic post and/or not realizing that Guiteau was seriously mentally disturbed.

Charles Guiteau’s Mistake: Believing you can make up for not getting a job by shooting your would-be employer in the back.

President Garfield’s Doctors’ Mistake: Operating. After Garfield was shot on July 2, 1881, a crack medical team led by Dr. Willard Bliss immediately moved into position to save his life. Their goal: Find and remove the bullet. Unfortunately, this proved to be difficult—and remarkably detrimental to Garfield. At one point, Bliss stuck his unwashed finger into the entry wound to fish around for the bullet. Later, a different doctor stuck his whole hand (up to his wrist) into the president’s gut—puncturing his liver in the process. In fact, if anything, Bliss and the other doctors turned out to be worse for Garfield’s health than the actual bullet. Over the course of the next 79 days, 16 of the country’s “finest” doctors managed to turn a 3-inch hole into a 20-inch long, festering tunnel. What’s more, telephone inventor Alexander Graham Bell joined in for a last-ditch effort to find the bullet—using a metal detector. And while his contraption did register metal in Garfield’s body, it seemed to be spread across such a wide area that the bullet was impossible to pinpoint. The likely reason? Bell forgot to account for those pesky metal springs inside Garfield’s presidential bed.

After the president finally succumbed to his physicians’ ministrations on September 19, his autopsy revealed that the bullet had come to rest in a spot that wasn’t life threatening at all. If the doctors had simply left him alone, Garfield would have recovered. Public reaction to this revelation was predictably harsh. Bliss and his cohorts were accused of malpractice, and even the assassin joined in the jeering. In fact, during his trial, Charles Guiteau put the blame squarely on the doctors. “I simply shot him,” Guiteau said. Accurate or not, his defense didn’t work. Guiteau was convicted and hanged.

This summer, we’ll be re-running parts of “The 20 Greatest Mistaikes in History,” Maggie Koerth-Baker’s cover story from March-April 2007. For other installments, click here.

Shhh…super secret special for blog readers.