I stand to be corrected but didn't Trump say when the Obama shut down happened, "The leader must take responsibility" or words to that effect.
Exactly.
Also, Trump in May and also the fall of last year said that "maybe we need a good shutdown".
Also, Trump has so confused even members in his own party, including McConnell and Ryan, that both commented that they didn't even know what he wanted.
Also, Trump has repeatedly said that he wants a deal for DACA, but over
one full year he has not proposed nor accepted any proposal on it.
Also, it is clear that Kelly, Cotton, Perdue, and especially Miller have his ear, and they're hardliners all the way, with the latter being a "white-nationalist" (Trump has quoted their "literature" btw). They clearly don't want these Hispanics in the country, and they don't care who gets hurt or killed because of it, such as with the 200,000 or Salvadorians and many Chaldeans that may be deported back to a very hostile country.
Also, Trump wants to appeal to his base that is chocked full of those heavy into ethnic and/or religious bigotry. Since Trump and the Pubs have lost most of the moderates, losing that base would be even more catastrophic for them politically.
To them, it's all about politics-- not the country.