I thought the senior adviser to the President, Laura Ingraham, had told Trump not to sign it?
So now there's an emergency. Because there is a bi-partisan bill now signed. An emergency that just arose, even though illegal border crossings have been dropping, and actual border patrol officials say there is no emergency.
He's perfectly happy to have it tied up in court. I'm guessing because we're in unprecedented territory here, but the moment he signs the declaration there's a federal lawsuit, and an injunction possibly by landowners who loses property to eminent domain. It could be years before $1 gets applied to wall construction. If Trump tries to take disaster funding away from California (or any other state) I'm sure that state would be in court the same day. He gives zero fucks about a wall, but this way he can say he tried and thus save face. He can be the hero to his fans. The hero who tried his best but was thwarted by Outside Evil Forces. Trump needs to position himself as the Noble Outsider, Valiantly Fighting the Corrupt Government/System, Treated Unfairly But Still Struggling to Help "The Little Guy".