Nothing prevents them from doing exactly the same thing-  That's the whole point of the exercise.  His leverage was the shutdown, their leverage was withholding the SOTU and workers not being paid.  Pelosi said "open the government first and we will negotiate"  DJT: "ummm OK the government is now open- you now have 21 days to work out the deal - I'll still give you everything you want for my 5.7B for the wall... 21 days will go by Nancy will probably still say NO 5.7 B for the WALL... DJT's response " OK Nance, the Caravan is that much closer so I'm declaring the National Emergency, I really didn't want to do this but you left me no choice- I'll now be using the 25B from the portion of the Military Defense budget that we agreed on with the last omnibus bill I signed after Cryin Chuck's shutdown... The wall is getting built one way or another Nancy, Oh and by the way  DACA and TPS are now off the table" for what will now be known as the PELOSI SHUTDOWN. Just my humble opinion -  who really knows how this all plays out-