Where is the evidence that 90% of drugs are imported?
without closing the border.
Since drugs can be hidden in legal imported goods, how do you propose we close the border to that traffic without bringing all importation to a grinding halt?
Well, if nothing else common sense. There is no poppy and coca plants being grown in this country that could deliver the demand. The occasional MJ grow you find on private property and national forests also is logistically incapable of delivering the amount of product used. Also, the precursor chemical regulations basically dried up the old style meth labs and the ephedrine labs you see at homes and hotels also cannot deliver in bulk.
That is where the increase in government in the form of customs and border patrol in lieu of Dept of Education, EPA, and DOE mutts is acceptable. IMO. They would be focused outward instead of looking inward at us.