It is easy to blow massive holes in the main refer myths in a line or two.
1) Saying that potent pot is reason for keeping marijuana illegal is akin to saying that alcohol should be banned because gin has higher alcohol content than beer. It makes no sense.
2) If today's marijuana is truly different in kind from "dads marijuana", would it be ok to legalize "dad's marijuana", i.e., low potency pot?
There is no causation without correlation. There has been an astronomical increase in the number of pot smokers since the 1950s and no increase in the rate of schizophrenia whatsoever.
Every time someone goes to buy marijuana they come into contact with criminal elements with access to other hard drugs. This is your gateway. When Holland legalized consumption and made it available in stores, heroin and cocaine use went down.
The Americans will not like it
1) I am not going to send people to jail for breaking a law Canadians do not think is just. I not going to do it.
2) It is one thing to remain silent, for example, on American foreign policy for fear of damaging trade relations. It is quite another to send someone to jail in order to placate the US.