reason # 1 :
People deserve freedom to use marijuana.
The first and most basic reason that marijuana should be legal is that there is no good reason for it not to be legal. Some people ask 'why should marijuana be legalized?" but we should ask "Why should marijuana be illegal?" From a philosophical point of view, individuals deserve the right to make choices for themselves. The government only has a right to limit those choices if the individual's actions endanger someone else. This does not apply to marijuana, since the individual who chooses to use marijuana does so according to his or her own free will. The government also may have a right to limit individual actions if the actions pose a significant threat to the individual. But this argument does not logically apply to marijuana because marijuana is far less dangerous than some drugs which are legal, such as alcohol and tobacco.
SUMMARY: Individuals deserve the right to decide whether or not they should use marijuana. The government should not tell individuals what to do as long as they do not harm others.