You can target groups by making things they are more likely to do illegal.

Or just stereotype the behavior as “things these people do” and accuse them of it in a judiciary stacked with bigot judges and prosecutors. Over 90% of cases end in plea bargains anyway, so you rarely have to worry about sorting a jury for doubters or nullificationists.

Just say “I smell weed” and throw a bag in the back of someone’s car. Viola! Instant prison sentence.