As he fights for re-election, Canadian Prime Minister Stephen Harper is once again trying to position himself as a crusader in the war on drugs — and cast his opponents as naive about the risks of liberal drug policies.

"We understand that illicit narcotics destroy lives," Harper said Tuesday as he promised to boost funding for the Royal Canadian Mounted Police to target the production of illegal drugs — including meth labs and marijuana grow-ops — and create a national phone hotline for parents to get advice if they fear their kids are using drugs.

"We understand they can rob young people of their futures, they can tear families apart, lay waste to communities, and make our streets unsafe," said Harper. "The bottom line is this: the drugs are not dangerous because they are illegal, they are illegal because they are dangerous."

The spiel from the tough-on-crime leader, however, was the last straw for a group of scientists who say his rhetoric is divorced from science. On Wednesday, the International Center for Science in Drug Policy (ICSDP) wanted to set the record straight and released a summary of scientific evidence to debunk common claims about the dangers of marijuana.

"There is a serious danger that the repetition of false claims, especially by our country's leaders, will lead to policies that further put our young at risk," the ICSDP, a group of doctors and drug policy scientists and researchers, said in a press release.

The group is led by a Toronto epidemiologist and researcher who was named a 2012 Trudeau Foundation Scholar, an independent research body named after former prime minister Pierre Trudeau, father of current Liberal leader Justin Trudeau.

The younger Trudeau has long expressed an interest in liberalizing Canada's drug policy, and marijuana legalization is now part of his party's platform in the ongoing federal election campaign.

The drug policy researchers published two summaries of scientific studies, one on the health risks of cannabis use and another on the consequences of cannabis legalization, both showing that a number of claims that Harper and other anti-drug politicians have made are not supported by the evidence.

The authors wrote that there is "weak" evidence marijuana lowers IQ, acts as a gateway drug or is "as addictive as heroin." They said studies regularly cited to show that smoking weed leads to cognitive problems or poor school performance don't control for confounding variables, while claims about pot-triggered schizophrenia can't account for the stability of the disease in the face of rising marijuana use. Evidence on many points is mixed or inconclusive, they pointed out, and opponents of drug reform are guilty of "cherry picking" evidence to support their agenda.

Harper is known for his tough-on-crime views and unwavering opposition to marijuana legalization. He has introduced legislation imposing mandatory minimum sentences on drug traffickers, which was later struck down by the Supreme Court, and has fought to shut down Vancouver's safe injection site, a project roundly supported as effective by researchers.

Harper has also made claims that marijuana legalization would make the drug more available, particularly to children.

"When you go down that route, marijuana becomes more readily available to children, more people become addicted to it, and the health outcomes become worse," Harper said on Tuesday. "I think it is actually a tragedy."

But the ICDSP report cites several studies that debunk Harper's argument. They wrote that countries with liberal marijuana laws, such as the Netherlands, actually show lower rates of use than countries with a more punitive approach.

"Just yesterday, Stephen Harper stated that cannabis legalization would only serve to make drugs more accessible to our children," the group said in a press release. "In fact, we've seen sustained, high levels of cannabis availability among youth in Canada under our current policies."

Similarly, they found little evidence for claims that legalization would lead to drug tourism, more impaired driving or the advent of "Big Marijuana" companies on the model of the tobacco industry. Fears about a spike in crime are also misplaced, they argued, since the current prohibition model means "100 percent" of drug proceeds now go through the hands of illegal traffickers.

When asked for comment on the ICSDP's claims, a spokesperson for Harper referred VICE News to "the PM's comments on the alternative positions on drug legalization."

"Justin refuses to acknowledge the damage that drugs do to families and communities," and NDP leader Thomas Mulcair "supports dangerous, ideological policies that would encourage the use of drugs," the spokesperson said. He pointed to data from Colorado that shows a 1.25 percentage point increase in marijuana use among young people following legalization in that state.

The ICSDP addressed this study in their summary, saying that not enough time has passed since legalization in Colorado, and it's likely that people underreported their use of marijuana before it become legal.

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