Congressman Steve Cohen from Tennessee states in his letter to Drug Czar Gil Kerlikowske that, "There is no evidence that marijuana has the same addictive qualities or damaging consequences as these harder drugs and it should not be treated as such." He goes on to explain how drug convictions for non-violent possession "crimes" have high costs - almost $7.6 billion per year is estimated to be spent on marijuana arrests and prosecutions. He also states that the damage to ruining someone's life with an unnecessary conviction is an unreasonable cost to our society, dooming these people to "second-class citizenship". He mentions the "disastrous racial disparities" in the criminal justice system, reporting that African-Americans and Latinos are much more likely to be arrested for marijuana possession than whites.
Congressman Cohen also addresses states' rights to make their own medical marijuana laws, stating, "We should not deny the thousands of Americans who rely on the benefits that marijuana provides. I strongly recommend that this administration allow states that have chosen to legalize medical marijuana to enact strong regulations without fear of prosecution.
You can read the Congressman's letter here