The court needs to decide whether to uphold a Cape Town High Court decision that a ban on lighting up a joint in the privacy of one's own home is unconstitutional.
In response to a case brought by Prince and Jeremy Acton of the Dagga Party of South Africa, the High Court decided in March laws that banned private use of dagga in a person's home violated the constitutional right to privacy. It ordered parliament to remake laws governing the cultivation and private use of dagga within two years.
But the state appealed against the decision in the highest court in the land.
Thomas Bokaba SAC, representing the state, said smoking dagga increased crime, affected the poor the most and caused mental illness and psychosis.
He was unable to answer repeated questions from Justice Mbuyiseli Madlanga on how legislators could decide to allow alcohol, which is harmful, but ban dagga.
Because Prince and Acton are both representing themselves, the court asked Ron Paschke SC to present evidence as an "intervening party".
Paschke labelled the state's evidence "inadequate" and said the state had failed to prove its case that banning dagga was less harmful than allowing it.