There is a card Trump has not played yet and it's one that might give him a lot of leverage in the shutdown showdown.
Right now, Trump is playing the "The military will build the wall if a humanitarian crisis is declared" card but that is the wrong way to go if he wants to sway the Democrats.
The card he needs to play is the jobs card, or more specifically, the union jobs card.
Today's edition of the Washington Post reports that building a border wall could require 10,000 workers working 10 years. That labor force would not be able to finish a complete border wall in that time frame, but that is the number of workers and the amount of time required to make meaningful progress on a border wall according to some.
So if it's an option to have union workers build the wall, Trump needs to say so and promote the potential for 10,000 union jobs for the next 10 years. How many Democrats would vote against ten years of employment for union workers?