Explained: When the US President speaks to the people

President Donald Trump delivered the State of the Union address, with Vice President Mike Pence and Speaker of the House Nancy Pelosi, at the Capitol in Washington, DC on February 5, 2019. Doug Mills/Pool via REUTERS

President Donald Trump's State of the Union (SOTU) Address to Congress in Washington DC on Tuesday night was his second, and the 96th in-person Address/Annual Message in the history of the United States. Franklin D Roosevelt's 1945 address was read to a Joint Session of the US House and Senate - since the President did not deliver it himself, it is not officially counted as an in-person address.

ORIGINS: According to a historical note on the website of the US House of Representatives, the formal basis of the State of the Union Address lies in the US Constitution: Article II, Section 3, Clause 1 states the President "shall from time to time give to the Congress Information of the State of the Union, and recommend to their Consideration such measures as he shall judge necessary and expedient".

From 1790, when President George Washington delivered the first of these messages, to 1946, the address was formally known as the Annual Message. Between 1942 and 1946, it was informally called the "state of the Union" message/address; since 1947, when President Harry S Truman gave his message to Congress (January 6), it has been officially known as the State of the Union Address.

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CONTENT: Annual Messages by earlier Presidents included agency budget requests and general reports on the health of the US economy. Subsequently, Congress required more in-depth reports on these aspects, separate from the Annual Message. The Budget Message was instituted by a 1921 law, and the Economic Report by an Act of 1946.

Since 1913, when President Woodrow Wilson revived the practice of speaking to Congress in person after a gap of 113 years, the SOTU has served as a platform for the President to rally support for his agenda. President Calvin Coolidge gave the first SOTU address to be broadcast on radio (1923), President Truman presented the first televised address (1947), and President George W Bush delivered the first address that was webcast live (2002) - consistently enabling Presidents to speak directly to increasing numbers of the American people.

On December 13, 1913, Woodrow Wilson gave the first in-person Annual Message since President John Adams on November 22, 1800

WHERE, WHEN: Modern SOTU addresses have been delivered in the House Chamber. Prior to the move of the Capitol to Washington, DC., the Annual Message was often delivered in the Senate Chamber. A House concurrent resolution sets aside the day and time for a Joint Session to receive the communication. Until 1934, the Annual Message was delivered every December; since then, the Annual Message/SOTU has been delivered every January or February.

LONGEST, SHORTEST: The longest written address was by Jimmy Carter (33,667 words) in 1981; the longest spoken address was by Bill Clinton (9,190 words) in 1995. The first address, by George Washington in 1790, was the shortest - 1,089 words.

The average address in the 19th century was about 10,000 words; from the late 20th century, it has been about 5,000 words.

FDR gave the most Messages/Addresses - 12, of which 10 were personal appearances before Congress. President Zachary Taylor delivered only 1, and Presidents William Henry Harrison and James A Garfield, none.