Does buying pot send money to Mexico or Colombia and does it cause people in those countries to be murdered?

There were thousands of killings of innocent people in Colombia 10 years ago due to the drug trade. America is the largest consumer of south American illegal Drugs. Now the murder rate in Mexico is going thru the roof in drug wars and the illegal drug trade is closer to the USA than it was before. So the real question is.. Can we apply legal punishement to college students for funding the Drug/Murder trade?