could do an even better job of it this time with all of the identification methods
They can’t even keep tract of tens of thousands of Sex offenders.
There is a difference between tracking and monitoring, and being able to identify someone. The point isn’t to monitor them and keep track of them, like we monitor sex offenders. Why would we care what they are doing in Mexico or where ever? We don’t care. The point is to be able to identify them, if they return, as previously having been deported. Returning here after you have been deported is a felony, and if you are caught here again, you are liable for up to 10 years in prison.