Most of what I read suggests that he might be fine in seeking the emergency status (because there doesn't seem to be strict guidelines on what qualifies as a national emergency) but he isn't going to be able to redirect the money for it. As I understand it - he declares a nat'l emergency. Then he has to file something describing what the emergency is and how he plans to address it. For the wall, that means stating where he plans to build it and, more importantly, how he plans to fund it. The Nat'l Emergency Act gives him 2 options. One is apparently DOA. The 2nd is only his only real option and it turns on whether or not a wall is necessary for the military to do its job (if it is, he can redirect military funding to the project). The losing prospect is that immigration enforcement and border enforcement are not within the military's scope. Additionally, the military is only allowed to engage in military construction - that is very specifically defined by Congress and the wall most likely does not meet that definition. So, I guess his only real option is to find an interpretation of military construction that allows him to re-frame an immigration border wall as a military necessity. Unfortunately for him, his own language is going to undermine his argument here, imo.