Trump did not declare a national emergency last night. I strongly suspect he had planned to, though. After all, the staging was there.
A prime time Oval Office formal speech. The President, grave and solemn as he sets the stage for an emergency declaration. Days of hints (in order to bolster the audience numbers). Minions out and about ponderously declaiming how everything is going to hell on the southern border.
I suspect the networks also bet on his declaring a national emergency. If they knew he was just going to dish out the usual, they wouldn’t have given up their ad revenue.