Of course this is a huge debate in our country right now and I think both sides are lying. The government wants control because they see $$$$$$$$, either in production or prosecution. The War on Drugs is an effort to keep the right happy while holding open the backdoor for traffickers. Foresight is not a human being's strong point so trying to predict what will happen if it's legalized is just shooting arrows at stars. It's something to do but it won't get you anywhere.
I think everyone over the age of 18, and in certain cases those under the age of 18, should have access to legal marijuana for whatever the need or reason. Whether you want to smoke it or eat it or sit there and stare at it all day (the good stuff really is pretty), fine by me just chill the fuck out.
Regular users build up a tolerance just like a person on anti-depressants. I suspect most citizens who want to keep it against federal law have only smoked occasionally. No different than the kid who goes to the bar on his 21st birthday having never had a drink in his life and taking four shots in an hour. He's going to be stone cold drunk and puking in a matter of hours. He'll probably never drink again and warn everyone else of its dangers. Same as the person who goes sky-diving for the first time, lands wrong and breaks their nose. They'll probably never recommend jumping out of a plane unless it's a matter of life and death.
...Yes, it should be legal.