It might not matter that Trump announced this as the spending bill worked its way forward. For example, we know his campaign statements were supposedly enough to stop him from exerting his Presidential power in area of national security.
I would not be surprised if a leftist judge is waiting in the wings waiting to halt the building of the wall either on environmental grounds, or more more likely that it discriminates against an entire class of people who have connection to regions south of the border.
let it be so.