When Eisenhower took office, the Korean War ended and the unemployment rate was over 7%. The took 1 million illegals, used boats and army buses and dumped them 200 to 400 miles into Mexico and dumped them off the beaches.
The unemployment rate within a short time dropped to 5%. Eisenhower said they were taking jobs from his returning troops.
No one complained back then and illegals didn't vote or pay taxes. Most were just farm hands.
When people came from Europe and wanted to register in the US, they had to go through Ellis Island. We knew who were coming in and where they came from. They were also given medical exams. If they had any disease, they sent them back to where they came from on the next ship out. If women were pregnant, they also sent them home because they didn't want their kids to become American citizens.
So, what part of registering at the border, with a passport, finding out who is coming in, whether they are criminals, diseased, or what ever, is hard for them to do. One big problem is in their countries, they can't get a passport for over a year or two. We offered to computerize Mexico's records, birth certificate, criminal records, etc. Mexico refused our help.
So arrest all the criminal illegals like Trump is doing first. Then find all the unmarried men and women and send them home. Then if an illegal is married to an American citizen, make them go through the citizenship school to become an American citizen BEFORE they can get any benefits. Right now Trump only has enough people to go after those who have a criminal record in the US and in the country they were from. This is not Gestopo tactics. They are not being rounded up and sent to concentration camps, Trump is sending most back to their home country. If they go to prison in their home country it is for a reason.