The U.S. drug policies as of the 30's, has made certain drugs illegal. Since they are illegal, their make up, strength, etc. cannot be known. This makes these drugs dangerous. Marijuana is the exception as it is a known commodity with known effects and mostly known strength. We find in States that have legalized recreational Marijuana, there is State regulation and they are assayed as to their strength.
I agree with Trump's policies for drugs like Fentynal, Cocaine, Heroin (for example) because no one can assess what is in a white powder or pills. I am for legalizing these drugs so they can be known as to what exactly is in them and the strength but I doubt if Trump will do this.