He 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.— Article II, Section 3 of the U.S. Constitution
Doesn’t say how.
In fact, from Thomas Jefferson through to Woodrow Wilson, 1801 – 1913, the State of the Union was delivered by letter – Jefferson being of the opinion that to summon Congress to hear the President was too akin to the monarchal Speech From The Throne. So Wilson going back to summoning Congress makes sense…
So there is vast, if old, precedent to not delivering the SOTU before Congress. So Pelosi scores no points by ‘canceling’ the address.
What she has done, and I hope Trump dunks on her for it, is allow him to deliver the speech wherever the hell he wants. For example, in front of ten thousand supporters at a stadium somewhere. With no opportunity for Schumer & Pelosi to repeat their dismal rebuttal act from last week’s national address about border security.
This is a gift, delivered and wrapped by an opposition that is coming apart at the seams. Take it, make the most of it, and never look back.
No one ever lost by allowing their enemies to be foolish, and make avoidable mistakes.