The presidential inauguration of Donald Trump fast approaches. If you are, let’s say, less than satisfied with the president-elect, you may find yourself mournfully counting down the hours until Trump takes over the Oval Office and wondering at what time, exactly, Obama will no longer be president. As part of a tradition extending back to the 1930s, Obama will officially cease to be president at 11:59:59 on the morning of January 20, ceding the office to Trump at 12 pm sharp. You may want to stock up on tissues.
The January 20, 12 pm, start time of all new presidents was codified into law in 1933, when the states ratified the 20th Amendment to the U.S. Constitution. Prior to that point, all U.S.presidents (other than George Washington himself) had been inducted into office on March 4. The March 4 inauguration created a lame-duck period of almost four months between when a president was elected and when he took office. Although, as Atlas Obscura points out, there were some valid reasons for the delay (including the fact that, in the days before high speed communication, tallying an election took a long time), the long gap also created some significant problems for both the exiting and incoming presidents. One prominent example occurred during the long gap between Abraham Lincoln’s election in 1860 and his inauguration months later; while he was waiting to take office, Southern states seceded from the Union, formed the Confederacy, and took control of federal military resources. There wasn’t anything Lincoln could do until March, when a lot of damage had already been done.
Franklin D. Roosevelt faced a similar problem with the gap between his election in 1932 and his inauguration in March of 1933, during which time he was unable to take action to relieve the economic stress of the Great Depression. In 1932, Congress proposed a Constitutional amendment to bump up Inauguration Day. Amendment 20, as it now stands, specifies that all presidents be inaugurated on January 20 at 12 noon.
Although Obama is clearly winding down his presidency, he will continue to hold the full power of the presidency until 11:59 am on Inauguration Day. After that, he’s a free man, and Trump will be president.