Ron Paul began is career as a physician. From a medical perspective he understands the need for the drug to be legalized. He has been a strong supporter of allowing the state to decide on the issue. 

Recently, Congressmen Paul and Barney Frank introduced a bill that would let states decide their own marijuana policies without federal intrusion; this was not just about medical marijuana policies. The Marijuana Policy Project (MPP) - a cannabis advocacy organization in the United States - has lobbied Congress for five years to initiate this legislation, which MPP helped to draft. At least 21 House members are sponsoring this legislation, as of today. International Business Times