Now if it fails in the Senate the shutdown is on the Democrats. Trump can speak every day, tweet every hour and remind Americans "your government is shut down because Democrats do not want a permanent, apolitical solution to the National Security threat at the Southern Border. After decades of speaking differently, they prefer illegal immigrants over the citizens of the U.S"
From what I gather, I actually do think Trump has the ability to build it with military funds. There's no question in my mind and by many metrics, you have a serious National Security threat. The Caravan might actually have been a Godsend to remind Americans the gravity of the threat.