As it currently stands, President Trump has decided to hold-off on making his SOTU address because he said he prefers to do so in the House rather than some other venue. If the partial shutdown continues to the point where he changes his mind, then, he might continue to be hampered by Pelosi's non-co-operation.
Pelosi wrote the POTUS on Wednesday:
"I am writing to inform you that the House of Representatives will not consider a concurrent resolution authorising the President's State of the Union address in the House Chamber until government has opened."
So she referred to a concurrent resolution.
A Joint Session is when "the House and Senate adopt a concurrent resolution to meet together to conduct formal business or to hear an address by the president of the United States."
https://www.senate.gov/reference/glossary_term/joint_session.htm
Note: "Concurrent resolutions are not submitted to the president and thus do not have the force of law."
https://www.senate.gov/reference/glossary_term/concurrent_resolution.htm
According to the House Rules, a concurrent resolution is "a means of expressing fact, principles, opinions, and purposes of the two Houses". And are used to authorize "providing for joint session to receive a message from the President".
"A concurrent resolution is binding on neither House until agreed to by both" and it is "not legislative in nature" so a concurrent resolution is not sent to the President for approval".
"A concurrent resolution is not a bill". "Where a choice between a concurrent resolution and a joint resolution is not dictated by law, the House by its vote on consideration of a measure decides which is the appropriate vehicle".
https://rules.house.gov/HouseRulesManual115/jefferson.xml#section-xxi
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It is interesting that while the President is empowered by the Constitution to convene either the House, the Senate, or both, the congressional response is to vote on a concurrent resolution which is does not have the force of law.
According to Roll Call:
If Pelosi does not agree to a joint session of Congress, Trump could opt to give the speech from the White House or hold an event somewhere else in the country. The president does have an affinity for political rallies, saying he enjoys speaking directly to his supporters.
Some Republicans have suggested that if Pelosi won’t host Trump, that Senate Majority Leader Mitch McConnell should hold the State of the Union in the Senate chamber. But McConnell cannot host a joint session of Congress without Pelosi’s signoff via House adoption of a concurrent resolution.
The speech does not need to be delivered live before a joint session of Congress or in late January, as has been tradition. The only requirement laid out in the Constitution is that 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.”
https://www.rollcall.com/news/congress/state-union-status-unclear-white-house-seeks-keep-jan-29