What is the State of the Union?

On Tuesday night at 9:00 a.m. EST, President Barack Obama will be front and center before the United States Congress to deliver his fifth State of the Union address, an annual speech in which the president will outline his agenda and plan of action for the next year.

The practice of issuing the State of the Union dates from the Constitution of the United States, specifically the following command:

"[The president] shall from time to time give to Congress information of the State of the Union and recommend to their Consideration such measures as he shall judge necessary and expedient."

The first State of the Union was issued by President George Washington on January 8, 1790 in New York City, although it was known as the "President's Annual Message to Congress" at the time. Subsequent presidents have typically delivered their speeches annually in late January or early February.

The president can choose the time of the annual address. Obama specifically selected February 12th, the birthday of President Abraham Lincoln, as the date of his speech.

Sen. Marco Rubio (R-Fla.) will deliver the Republican response, while Sen. Rand Paul (R-Ky.) will give a response from the Tea Party. Those speeches will air subsequently to the State of the Union and focus on those politicians' alternate plans for the future of the country. Both Rubio and Paul are widely expected to launch presidential bids in 2016, though Rubio is the more credible contender, having both mainstream GOP support and the bonus of recently introducing a bipartisan immigration reform bill.