Donald Trump secretly authorised the CIA to spy on Venezuela in an escalation of his drug war with Nicolas Maduro, the country’s president.

The Trump administration has produced a classified legal opinion that justifies lethal strikes against a secret and expansive list of cartels and suspected drug traffickers, according to multiple people familiar with the matter.

The allegations in his case are a pointed example of when classified information tumbles into nonsecure places, either by accident or from recklessness by someone trusted to keep it safe.