Because 80% of hard drug users smoked cigarettes does not mean that 80% of cigarette smokers will become hard drug users.
In Poland before WWII 20% of the communists were Jews, but less than 1% of the Jews were communists. Yet many American leaders were hesitant to let Jews in to America because they were presumed to be commies.
There is a distinct difference between saying that half of those arrested for federal drug crimes are illegal immigrants and saying that half of illegal immigrants are drug criminals. Relatively few immigrants, legal or otherwise become criminals.
This is a common statistical fallacy that even the brightest fall for. There is a problem with immigration and there is a problem with illegal immigrants and sanctuary cities. These problems deserve consideration and real solutions. But Trump’s incendiary comments has translated its message into a false stereotypes and played on the peoples ignorance.
Of the 2200 charges for Federal Drug Crimes 3/4 were illegal immigrants. 3/4 of 2200 is 1650 charges. Assuming there are twenty million illegal immigrants in the country (a low estimate by some measures), 1650 is a minuscule number.
Beware of setting sweeping policies based on isolated anecdotes. The tragedy of Kathryn Steinle in San Francisco should spark an investigation into the handling of repeat offenders, illegal immigrants and sanctuary cities. But we must be careful that our pain and outrage is not used to wrongly disparage a larger population through statistical fallacies and manipulation.