Consider the case POTUS has to make for the Wall that will withstand SCOTUS & the court of public opinion.
He has to prove that existing law doesn’t exist before declaring a National Emergency.
He’s also demonstrated to Fed workers that he has the power to both shut down the government and reopen it. They now have a taste of how it sucks to not be paid and contrast it now with the next 3 weeks of getting paid.
So facing another shutdown in Feb over the wall, how many will cave to the Wall demands to keep the paychecks flowing.