The combined lessons of recent enforcement actions, judicial rulings and criminal investigations point to a decisive conclusion: legalising rhino horn, in any form, under any circumstances, will strengthen illegal markets rather than weaken them. The record rhino horn seizure in Singapore, the Kimberley High Court ruling in South Africa and the arrest of former breeder John Hume reveal how any legal opening for rhino horn rapidly becomes intertwined with the illegal market. As CITES CoP20 kicks off, the evidence overwhelmingly shows that legalising trade would accelerate, not deter, rhino trafficking.