I cannot figure any possible way that the United States' FEDERAL GOVERNMENT has the constitutional authority to criminalize (at the core) the act of someone planting a seed and smoking the plant.
American conservatives only need refer to our constitution for guidance on this.
...as for specially TAXING it. We are (or should be) AGAINST that. Although, objectively, I can't see getting that double dose of freedom restored at the same time. Restoring legitimate and reasonable taxation overall will be an ongoing quest.
Don't forget Washington mounting up to put down the Whiskey Rebellion.