The First Undisputed, Long-Term Presidential Disability
At the Baltimore and Potomac railroad station in Baltimore, Maryland on the morning of July 2, 1881, Charles Julius Guiteau pulled a .44 caliber British Bulldog pistol from his coat and fired two bullets at President James Garfield. One bullet produced a fairly superficial wound to the President's arm, but the other would glance off Garfield's ribcage and penetrate, coming to rest just behind his pancreas.
But unlike Abraham Lincoln sixteen years earlier, James Garfield's death would not come quickly. In fact, initial reports suggested that the President would make a full recovery; and modern analysis suggests that had Garfield done nothing more than applied clean dressings to the wounded area and been confined to his bed during the summer of 1881, full recovery would've occurred. As it was he was poorly treated by his medical attendants, lingering for 79 days while his health rallied and falled until, on September 19th, the President would die of infection. The Garfield assassination presented the United States with its first clear-cut case of presidential disability.
The Response: A Lack of Response
Unlike prior situations (e.g., Washington, Madison, William Henry Harrison and Zachary Taylor prior to their deaths) in which a President had fallen ill and gradually become less and less capable to discharge the powers and duties of the presidency, everyone immediately recognized that Garfield's recovery necessitated temporary relief from his responsibilities. Also unlike prior situations, Vice President Chester Arthur was encouraged, both by Congressional leaders and members of Garfield's own Cabinet, to take the reins as Acting President.
But Vice President Arthur demurred. Why? Essentially there were two reasons.
The first was that there was no defined means by which the Vice President could act as President. While the Constitution and the Presidential Succession Act of 1792 may have spelled out who should act in the President's stead, it didn't spell out how that was to actually take place. With no process spelled out by Congress as to how he could act as President and no precedent to follow, Vice President Arthur's hands were somewhat tied. While contemporary conventional wisdom believed that Arthur could act as President if a Joint Resolution of Congress declaring the President disabled were to be adopted by a two-thirds majority in both houses, that opinion wasn't universally seen as constitutional. Rather than potentially spearhead a violation of the Constitution and be seen as a usurper, Arthur did little but wring his hands and hope for the best.
But the legal aspects of an Acting President Arthur were just one consideration. The second, and likely more compelling, reason he declined to step in was the circumstances of Garfield's shooting itself. The President's assassin was known - known to Garfield, to Arthur, and to Secretary of State James Blaine, to whom Guiteau had repeatedly entreated in search of a political patronage civil service appointment. Apprehended after shooting Garfield, Guiteau proudly proclaimed, "I am a stalwart (a faction of Republicans that believed strongly in the spoils system and fought civil service reform; and a faction to which Arthur belonged) and Arthur is President now!" Under those conditions, Arthur's ascent to the presidency following Garfield's death was seen as suspicious enough; acting as President with Garfield very much still alive, even with Congressional sanction, would've been viewed harshly to say the least.
Late on the night of September 19, 1881, Vice President Arthur received word that President Garfield had died, a victim of septicemia. Upon receiving a telegram confirming the news the following morning, Chester Alan Arthur was sworn in as the 21st President of the United States.
Ironically, the man who shot a President because he couldn't get a government job would cause thousands of government offices and positions going unfilled for most of 1881, grinding aspects of the work of the national government to a halt until Arthur took office. And upon doing so, now-President Arthur, who had been added to the 1880 Republican presidential ticket as a pro-spoils system counterweight to the civil service reform-minded Garfield, stunned everyone by making civil service reform - the chief cause Garfield had championed - the first item on his presidential agenda. The end result was fulfilling Garfield's plans; the exact opposite of what Guiteau and his stalwart faction of Republicans wanted.