The 20th amendment of the US Constitution (added in 1933) states, "The terms of the President & Vice President shall end at noon on the 20th day of January..."
Now why that was the time set to begin with, I don't know.
The President is required to take the Oath of Office as written in the Constitution. However, the President assumes office at 12pm noon even without taking the Oath of Office.
I think the president becomes official at NOON the day of inauguration, whether he takes the oath or not.
Inauguaration
The oath of office is traditionally taken at noon.
Tomorrow morning he takes the oath of office at noon eastern time.
They are president at noon whether or not the oath has been taken. It's in the Twentieth Amendment of the Consitution.
It was approximately 1205 when he took the oath of office. However he officially became president at noon when George W. Bush's term ended. The verbal oath of office is a formality. noon
The outgoing President's term ends at noon, and the President-Elect automatically becomes President at the same time regardless of whether or not he's taken the oath of office. HOWEVER, he cannot act as President, or in effect "execute the office of President of the United States" until he's taken the oath. For example, the Vice-President normally takes his oath before the President. Assuming the VP's been sworn in a few moments before noon, he would constitutionally be "Acting President" until the President takes his oath.
at noon
The President promises to protect the natural (and governed) rights of the people when he takes the oath of office.
The Vice President would then take his place, until the number of votes needed to officially elect a new President is decided and reached.
No, the president is not the Oath Of Office.