Based on historical records, Trump is correct and we are in uncharted waters.
The story took yet another turn on Wednesday after Trump essentially threatened to waltz into the House chamber next Tuesday on the originally scheduled date of January 29 and deliver the address regardless of Pelosi's authority or wishes.
In a letter to the House speaker, Trump said "it would be so very sad for our Country if the State of the Union were not delivered on time, on schedule, and very importantly, on location!"
In response, Pelosi sent a letter to Trump informing him the House "will not consider a concurrent resolution authorizing the President's State of the Union address in the House Chamber until government has opened."
The House Speaker added, "Again, I look forward to welcoming you to the House on a mutually agreeable date for this address when government has been opened."
In this sense, Pelosi did not outright cancel the address, but informed Trump it is to be postponed and potentially rescheduled pending the reopening of the federal government.
Reacting to Pelosi's letter, Trump at a meeting on Wednesday said, "We just found out that she's canceled it, and I think that's a great blotch on the incredible country that we all love. It's a great, great, horrible mark."
Trump added, "I dont believe it's ever happened before, and it's always good to be part of history. But this is a very negative part of history. This is where people are afraid to open up and say what's going on. So it's a very, very negative part of history."
There have been cases in the past in which presidents have sought to deliver speeches to Congress that were not State of the Union addresses in which their requests were denied. Former President Ronald Reagan, for example, in 1986 was denied a request to address the House to make an appeal for aid to the contras rebel group in Nicaragua. At the time, House Speaker Thomas P. O'Neill Jr. rejected Reagan's ask as an "unorthodox procedure."
If Trump delivered the State of the Union address on January 29 and the shutdown was ongoing, he also would make history in that context.
It's not clear what Trump will do moving forward and during a Wednesday afternoon meeting said he was considering an "alternative" and that he'd provide more details later on.