"Most Canadians [...] do not want the full legalization of marijuana. Because they recognize [...] that when you go down that route, marijuana becomes more readily available to children[.]" --Canadian Prime Minister Stephen Harper, Conservative Party Leader, August 2015

"What is very clear right now is that Mr. Harper's current approach is making marijuana too easy to access for our kids[.]" --Justin Trudeau, Leader of the Liberal Party of Canada, September 2015

The Rebuttal: Does prohibition keep cannabis out of our children's hands or make it more available?

A 2009 study released by Columbia University's National Center on Addiction and Substance Abuse backs up Trudeau's claim that prohibition makes cannabis easier to obtain than cigarettes, beer, or prescription drugs.

However, a 2014 study challenges both Trudeau's and Harper's positions.

The Journal of Adolescent Health published a report analyzing cannabis consumption in legal states. Researchers compared those regions to neighbouring states where marijuana remains illegal. They found that cannabis consumption has remained steady among American teenagers over the last 20 years.

These findings undoubtedly disappoint folks both sides of the debate. For reformers like Trudeau, there doesn't appear to be substantial evidence to suggest that legalization will reduce the number of minors consuming cannabis. Conversely, the reports don't support Harper's argument that legalization will lead to a spike in teenage consumption.

However, a smaller study released by the Colorado Department of Public Health and Environment in 2014 suggests cannabis use among teenagers has declined steadily since the state legalized recreational use.

The CDPHE's survey doesn't have as broad of a scope as the report released in the Journal of Adolescent Health, but since research on this topic is in its infancy, all data should be considered.

The available evidence gives Trudeau a slight advantage on the issue. Harper, meanwhile, appears to be cherry-picking evidence to support his chosen position.

This is the first in a regular series called "The Rebuttal", where we'll take the statements of politicians on cannabis and test them against the facts at hand. Any suggestions? Please let us know in the comments section below.