According to Federal Laws, marijuana is an illegal drug which is categorized in to schedule 1 drug. Schedule 1 drugs refers to drugs that have no medical use and have no margin of safety in their use. Supporting this statement, the DEA very recently issued an announcement confirming that it also regards marijuana as a schedule 1 drug.
Basing on this announcement, a new memo has been sent to US attorney saying that marijuana is illegal under federal law. They also said that any large scale operations or multi million dollar operations will be prosecuted even if they are operating under state law. This new policy made drug reformers worried about their medical marijuana cultivation.
However, this new policy is not clear about the mid level dispensaries. These dispensaries are operating under the state laws and also they are not involved in multi dollar operations. They seem to be serving the population that has medical marijuana recommendations from the physicians.
Since this is a central problem with growing number of states that has legalized medical marijuana the guidance memo encourage prosecutors to go after some marijuana dispensaries which are carrying the large operations.
This might be a positive sign to the prosecutors but not for the dispensaries. However laws like this should certainly encouraged to save the lives of many people and to avoid the fake marijuana cultivators who are doing hundreds of millions of business every year by spoiling the lives of many people.