Cameron stuck to his guns and he still looks like the favourite to become Tory leader. His decision not to tell us if he has ever taken drugs may even have strengthened his cause. We can be fairly confident that if Cameron had never taken drugs, he would be happy to tell the world about it. He would have had three choices: tell a fib, tell the truth, or not answer at all. Like most politicians, Cameron's instincts would have been to tell the truth.
I remember when New Labour put out a 'line to take' following the declaration by some top Tories that they themselves had smoked cannabis. This followed Ann Widdecombe's 2000 anti-drugs speech to the Tory Party conference, which some colleagues decided to scupper. The media wanted to know if Labour ministers had also taken dope in their youth, but the edict went out to not answer the question. One minister rang me up for advice as she was going on Any Questions that night. She had the odd spliff at college and wanted to admit it. My advice was to stuff Number 10 and tell the truth - she did and no one gave a monkey's.
But what if she had snorted cocaine? If Cameron had taken the drug it would, given Kate Moss's hounding by the media, have been untenable for him to own up.
Maybe he looked across the pond for inspiration. Bill Clinton famously said that he had smoked dope but 'never inhaled', and got away with it.
It is quite possible George W Bush took drugs in his youth, with people quite happy to accept that he was too drunk to remember. Interestingly, though the Yanks are much less tolerant of drugs, their politicians don't seem to come under the same pressure that ours do.
Cameron went wrong by letting his smart-ass public school boy instincts take over. He clearly implied he had taken drugs at university, but declined to go further. Indeed, both he and his inquisitor in Blackpool, The Observer's Andrew Rawnsley - who also went to public school - giggled at the answer.
He must be praying that no one will come forward with claims of past indiscretions because if they do, and they involve cocaine, he could be seriously damaged.
Surprisingly, Labour is not behind this negative publicity - it's the warring Tories themselves.