To me, the bottom line is this: While both alcohol and marijuana are drugs that inebriate the user, we don't yet have a way to regulate or implement a road-side drug test for marijuana. At least not to my knowledge.
When you're pulled over and suspected of driving under the influence of alcohol, there is a quick roadside test officers can perform to determine if you're over the legal limit of alcohol in your system while driving a car.
But as of right now, how do we determine someone has had too much marijuana in their system to drive or operate dangerous equipment and is a danger to other people? What should that limit be, exactly, and how would it be enforced?
To me, we need to answer these questions and get our stuff together; have a plan and actually know what we're doing before we legalize any drug.