not really. there would still be a number of organizations like the FBI and others that would still prosecute for cannabis, it would not remove state laws, it would not reschedule cannabis...so yeah. that is just an uninformed thing to say, not to mention a great way of assuring no second term.
but i'm sure if obama did do that, there would be a vocal contingent here blasting him for abusing executive powers and acting like a tyrant. such is the no-win situation obama is faced with by those suffering manic ODS.