President Obama is slated to let Congress (and the rest of us) know how the country’s doing in his third State of the Union address on Tuesday night. Here are the answers to a few questions that might come up when the address storms every channel of your television.

Why does the President give a State of the Union address to Congress every year?

The address can trace its roots back to the Constitution. Article II, Section 3, Clause 1 of the Constitution says that 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.”

Isn’t that a pretty vague order?

“From time to time” leaves the question of frequency open to interpretation, but George Washington helped cement the State of the Union as an annual event after he gave the first State of the Union address at Federal Hall in New York City in January 1790.

Since there wasn’t much of a blueprint for Washington, he praised the 1st Congress’ work and outlined a brief legislative plan for the upcoming year. In this way, Washington’s address bore some resemblance to the one President Obama will give tonight. On the other hand, Washington’s goals were a bit different from national health care; he wanted to work on the army, build post roads, and develop uniform systems of currency, weights, and measures.

What if a President didn’t love public speaking?

You’ll notice that the order from Article II, Section 3 of the Constitution doesn’t say anything about a speech; the President just has to keep Congress informed of what’s going on in the country. When Thomas Jefferson took office in 1801, he decided that the idea of showing up before Congress to deliver a grand address sounded like something a monarch would do, so he decided to bag the speech. Instead, he wrote down an annual message and sent it to Congress, where a clerk read it aloud to the assembled legislators.

Would a politician really skip a chance to give a big speech?

Apparently Presidents don’t love giving long speeches any more than the rest of us do, because Jefferson’s successors jumped on this new system. For over a century, every President opted to keep Congress informed through a written message rather than a spoken one; these messages were generally full of long, exhaustive administrative and budget reports rather than rousing political rhetoric.

Woodrow Wilson finally revived the old practice of delivering a speech in 1913. Even then, Presidents haven’t always appeared to give a speech. Since the 1913 revival of the practice, 22 State of the Union reports have come in written form, most recently Reagan’s 1989 report.

Who are all of the people crammed into the front of the House Chamber?

It’s a big crowd for the State of the Union. In addition to the members of Congress, the President usually has the Justices of the Supreme Court, the Joint Chiefs of Staff, and his cabinet seated at the front of the audience.

Who won’t be there?

At least one member of President Obama’s cabinet. Since the Cold War, one member of the cabinet has holed up in an undisclosed secure location during big government gatherings like the State of the Union address and presidential inaugurations. This absent member is dubbed the “designated survivor.” In the unlikely event that an attack or a disaster leads to the deaths of all of the assembled leaders, having a designated survivor hiding out somewhere safe maintains the line of presidential succession.

Since 2005 a few members of Congress have also stayed away from big events so there would be at least a tiny legislature remaining in the event of a disaster.

When did the State of the Union address become must-see TV?

President Truman actually gave the first televised State of the Union in 1947, but it didn’t become a primetime spectacle until 1965. Lyndon B. Johnson decided to give his address in the evening that year, while previous addresses had generally taken place during the day. At the time, LBJ was trying to sell Americans on his civil rights reforms and Great Society plans, so he decided to give the address at night in order to reach the widest possible audience. The trick worked, and it was the first State of the Union address to be televised during the evening.

Can a President opt out of giving a State of the Union address?

Sort of. It doesn’t really make a lot of sense for a newly inaugurated president to deliver a State of the Union address after only having been in office for a few days. Since Ronald Reagan’s first term started in 1981, new presidents have opted to give a somewhat more specialized address—everyone but George H.W. Bush in 1989 has spoken mostly about the economy—to a joint session of Congress. Although these speeches are accompanied by the familiar pomp and circumstance, they’re not technically State of the Union addresses.

Who started the parade of honored guests?

Could such a Hollywood flourish have come from anyone other than Ronald Reagan? His 1982 address was the first to feature personal guests that the President publicly recognized over the course of his speech.

As you might guess, there have a few guests that one might not expect at a political event. A few particularly choice guests: 12-year-old music prodigy Tyrone Ford (1986), baseball sluggers Sammy Sosa (1999) and Hank Aaron (2000), Baby Einstein founder Julie Aigner-Clark (2007), and NBA star Dikembe Mutombo (2007).

What’s the story with the opposition party’s response right after the address?

In 1966, television networks offered the Republican Party a half-hour slot for a rebuttal of LBJ’s address. Senator Everett Dirksen and Representative Gerald Ford made counterarguments to Johnson’s comments. Since 1976, the opposition’s response has been slotted in directly behind the State of the Union.

Who gave the longest address in history?

According to the Office of the Clerk of the U.S. House of Representatives, Harry Truman takes that prize with a 1946 speech—over 25,000 words. (To give you an idea of how long that is, the average modern address is in the neighborhood of 5,000 words.) George Washington wins the award for brevity; his first address in 1790 was just 833 words long.

A version of this article originally appeared in 2010.

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