The State of the Union is, well, unclear.
Adding to the unprecedented nature of the longest government shutdown on record, Speaker Nancy Pelosi again revoked her invitation for President Trump to deliver his annual address in the House chamber.
In a tit-for-tat exchange, Ms. Pelosi said Wednesday that she would not grant Mr. Trump access to address a joint session of Congress until the government had reopened.
Here’s what we know about the precedent for the State of the Union — and what could happen next.
Does there have to be a State of the Union?
Yes, according to the Constitution.
In outlining the framework for the executive branch, the founding fathers determined that the president “shall from time to time give to the Congress information of the State of the Union.”
Once the opening of Congress was moved in 1933 to early January from early March, with the ratification of the 20th Amendment, it became customary to deliver the address in the first two months of the year. That address was formally known as the annual message until 1947, when the informal nickname “State of the Union” was officially adopted, according to the House historian.
However, both the House and the Senate need to pass a joint resolution that formally invites the president to deliver the address. Ms. Pelosi said on Wednesday that she would not allow a floor vote on such a resolution until the government was fully reopened.
The Constitution, however, doesn’t stipulate a deadline for the address, so Ms. Pelosi and Mr. Trump could theoretically continue their negotiations indefinitely.
Has a State of the Union ever been delivered anywhere but the House?
In modern history, no.
Before the capital moved to Washington from Philadelphia in 1800, the annual message was usually issued in the Senate chamber. Until 1913, it was typically written and given to both chambers of Congress — a practice started by Thomas Jefferson in 1801, according to the House historian.
“It was received basically as a legislative agenda,” said Eric Foner, a professor emeritus of history at Columbia University.
“When you’re not delivering it in person, there’s no incentive for flowery rhetoric or dramatic appeals,” he added. “Most of the State of the Union addresses are eminently forgettable.”
In 1913, President Woodrow Wilson, breaking with over a century of custom, delivered the address before a joint session of Congress. In doing so, he started a shift from an administrative report to a personal rally of support for the presidential agenda.
“Wilson had always wanted to do this; ever since he was a college student, he had not liked the separation of powers — he had wanted to bring the branches together,” said John Milton Cooper Jr., a biographer of Mr. Wilson. “He thought one of the best ways to do this was to give it in person and show that the president was a living, breathing person.”
Occasionally, however, presidents have reverted to the Jeffersonian practice of submitting the address in writing — typically because of illness or issues with scheduling. The most recent was President Jimmy Carter in 1981, who delivered a written version to Congress four days before Ronald Reagan was sworn in.
Has a president ever been refused access to the House chamber?
In 1986, Speaker Tip O’Neill, a Democrat, refused to let Mr. Reagan address the House before it voted on an aid package for the Contras, the Nicaraguan rebels. Mr. Reagan had hoped to persuade representatives to appropriate $ 100 million in aid, but Mr. O’Neill declined to allow him to address only the House, and instead offered the president the opportunity to speak to a joint session of Congress.
Mr. Reagan turned down that offer — the House “is who we want to talk to,” his aides said — and instead delivered his address on television. It was carried by only CNN.
What happens if the president just shows up at the Capitol?
Both the president and the vice president are allowed on the House floor, but to address the chamber, they, like any representative, must be formally recognized by the speaker, according to House rules.
As speaker, Ms. Pelosi controls the lights, microphones and cameras in the chamber. Over summer recess in 2008, she left Republicans, then in the minority, to protest her refusal to hold a vote removing a ban on offshore drilling in darkened chambers. And in 2016, Democrats, then in the minority, used Periscope and other platforms to subvert the rules and live-stream a sit-in on the House floor as they demanded a vote on gun control legislation.
What are the alternatives?
Past presidents have addressed Congress from the Senate chamber nine times, beginning with George Washington’s inaugural address in New York, and bookended by Gerald R. Ford’s separate addresses to the Senate and the House only days after Richard M. Nixon resigned.
But the State of the Union address has never been delivered in the smaller Senate chamber, and the president’s delivery of it there would present a number of challenges, including the Senate’s much stricter limitations on cameras and filming. This likely roadblock is something that a president famously fond of televised performance would have to work around. (Nevertheless, some senators have endorsed the option.)
Or as Mr. Foner, the professor, put it: “Trump could take the high road and say, ‘I’m going to be like Lincoln, and send it in writing.’” (The president has previously compared himself to Lincoln.)
Some have also seen the kerfuffle as a good opportunity for a speech outside Washington: Gov. Jim Justice of West Virginia, a staunch defender of Mr. Trump, offered Wednesday to host the president at his state’s Capitol if he were unable to deliver the address in Washington. Tim Moore, the speaker of the North Carolina House, made a similar offer.