When they see the money that Canada brings in from pot, the US government will look at legalizing also just from a tax revenue standpoint and to remove the black market from the picture. It is already legal in nine states for recreational use (and three more are voting on it next month) and a number of likely 2020 Presidential candidates plan to make it legal if elected. I saw a poll on TV today which said 60 percent of the American public favors legalizing it. My guess is it will be legal across the US if not by 2021 then by 2025 at the very latest.