You mean liberals and libertarians agree that using drugs should not be a federal crime? Many conservatives and Freepers would also agree. Many big government liberty killing conservatives like criminalizing personal choices. They have more in common with liberals than libertarians.
Reagan conservatives certainly do not believe in legalizing drugs. It's utterly moronic idea that diminishes the quality of life for everyone.
Your personal choice ends when start engaging in negligent behavior that endangers other people.
Let states handle as long as the states keep illegal. I don't care.