Americans are p*(#ed, President Trump is p*@)_^*ed but guess who is more p!**#ed? The drug cartels at the border. Last thing drug dealers want is the military at their place of business!
Only if they aren't getting paid. None of this would be happening except for payments to cartels and corrupt officials for passage through their areas of influence. If the cartels don't get money, then they don't want to be seen as participating when the US Gov't does a state of emergency situation. Too much risk of the Hellfire night visits.