Paul's Amendment 3630, filed Thursday morning to Sen. John Walsh's (D-Mont.) jobs bill being heard on the Senate floor, allows states to "enact and implement laws that authorize the use, distribution, possession, or cultivation of marijuana for medical use" without fear of federal prosecution. There are 33 states that have enacted laws protecting some form medical marijuana.

The amendment also prohibits prosecution of patients and physicians in those states for violating federal laws against the drug.