News conferences with Canada's Prime Minister don't happen every day — which, of course, increases the likelihood that, when he does hold one, he'll make news.

But it's even rarer that you'll hear Stephen Harper concede that the war on drugs is a failure.

It happened, though, after two days of listening to Latin American leaders explaining just how costly, and bloody, the war is.

Harper met Canadian journalists at the summit in Cartagena, Colombia, on Sunday and readily admitted there are differences among the leaders over the exclusion of Cuba from the Latin America summit. He admitted, too, that there was a disagreement over British rule in the Falkland Islands.

But Harper was not ready to agree that the division over drug policy is so clear-cut. Rather, he insisted that there is much agreement. Then came the most interesting quote of the day.

"What I think everybody believes," Harper said, "is that the current approach is not working. But it is not clear what we should do."

This would be intriguing from any prime minister. From Stephen Harper, whose government's crime bill ratchets up the penalties for drug possession, it was startling.

Lest anyone think he'd undergone a conversion in Cartagena, Harper quickly added the other side of the story.

Drugs, he said, "are illegal because they quickly and totally — with many of the drugs — destroy people's lives."

Was marijuana the exception he had in mind? We never got to ask. But perhaps that was enough eyebrow-raising for one day.