4/20 was the California State police code for drug crime.  The arbitrary deadline April 20 (4/20) is a ploy to win friends among the pot heads of the nation for the annual day of  protest. They want it to be a day of pot victory.  It has nothing to do with what is for the good of Canada as such, but rather to glean the stoner vote, assuming they vote at all.  This is juvenile  of Justin to take his marching orders from them to meet their dead line rather than to do it properly.  But I never expected anything better of him.