Defenses to drug charges often deal with whether there is a legally proper basis for a car stop, or detention of a person.

Further, there must be a probable cause for a search, or a proper consent, or the drug and other evidence observed is not admissible in court.

Also, in many cases, there is a legal issue about whether the State will be able to prove construction possession. Constructive possession is when the drugs are not on the person, but are nearby.