NOTE:  This is partly political, and Trump is using Joseph Goebbels (head of Reich Ministry of Public Enlightenment and Propaganda) playbook.  Identify a person or group and use them to (falsely) blame them for all ills in your nation.  In Goebbels' case the Jews, in Trump's case immigrants.

"How Trump’s border decisions represent ‘completely new’ American policy" PBS NewsHour 11/26/2018

Excerpt

SUMMARY:  As Immigration policy takes center stage, we analyze the administration's recent moves on Border closures and asylum requests.  Scott Shuchart worked on immigration for the Department of Homeland Security under both President Obama and President Trump.  He's now a senior immigration fellow at the Center for American Progress and a Washington Post contributor, and he joins Amna Nawaz to discuss.