Given that scenario, the question is whether Lincoln would have recovered sufficiently to return to office, says a doctor and historian who planned to speak Friday at an annual University of Maryland School of Medicine conference on the deaths of historic figures.
While the conference has traditionally re-examined the deaths of historic figures to determine if the diagnosis of the time was correct, this year's event asks if Lincoln could have been saved and what impact that would have had.
Dr. Thomas Scalea, the physician in chief at the University of Maryland's Shock Trauma Center, said brain injuries are unpredictable but that Lincoln would have stood a good chance of surviving.
"It's a little hard to know, but I think it's a fair statement to say this is not necessarily a fatal injury; he doesn't have to die," said Scalea, who will explain how Lincoln would have been treated at his center, the world's first dedicated trauma center.
Lincoln died within 10 hours of being shot in the head at Ford's Theatre on April 14, 1865. If modern methods could have saved the 16th president, he might also have retained his cognitive abilities, because the fatal shot did not damage the frontal lobes of Lincoln's brain, the areas responsible for language, emotion and problem solving, Scalea said.
However, Lincoln would have faced months of recovery before he could have returned to office, and whether he would have been able to communicate is unclear, the surgeon said.
U.S. presidential historian Steven Lee Carson said Lincoln's secretary of war, Edwin Stanton, who made a number of important decisions the day after the assassination, would likely have played a greater role if Lincoln had survived.
Vice President Andrew Johnson would not automatically have taken charge had Lincoln lived because the 25th Amendment, which deals with the transfer of power when a president is incapacitated, was not in place until after the assassination of President John F. Kennedy in 1963. The decision as to who took charge was handled on a case-by-case basis until then, Carson said.
For example, Woodrow Wilson's wife essentially took over when her husband fell ill, Carson said.
Johnson, who took office after Lincoln's death, was the only Southern senator not to leave office upon secession. Lincoln had put him on the presidential ticket as a symbol of unity, but Johnson was a southern Democrat who was not sympathetic to Lincoln's Republican Party or to helping the newly-freed slaves, said Carson, who will also speak at the conference.
If Stanton had continued in Lincoln's place, the country "would have been a better and more just nation, especially on race matters, in a far quicker fashion," Carson said.
Johnson eventually tried to replace Stanton, an abolitionist and a close friend of Lincoln, which led to the attempt by Republicans to remove Johnson from office by impeachment.
Previous conferences have examined the deaths of Alexander the Great, Mozart, Beethoven, Edgar Allan Poe and others. This year's event is part of the School of Medicine's bicentennial celebration and the annual reunion of its Medical Alumni Association.
This is not the only recent news involving the health of the 16th president: An article in the current issue of the Journal of Medical Biography claims that, shortly after giving the famed Gettysburg Address in 1863, Lincoln was infected with unmodified smallpox, and that doctors tired to assure the public that the president — who was suffering from dizziness, headaches, back pains, a scarlet rash and lesions — was not seriously ill.
That Lincoln survived suggests, the paper's authors claim, that Lincoln was partially immune to smallpox (or varioloid, its old name).
Lincoln's penchant for humor did not weaken with illness. He told acquaintances, "For once in my life as President, I find myself in a position to give everybody something!"