Citizens of Colorado and Washington have voted to legalize marijuana for recreational use to be regulated in a similar manner to alcohol (for people over 21 years of age from licensed vendors).
It has been over 6 months since Eric Holder stated the government would provide a response to this legalization "relatively soon".
As it stands, the states have not been informed as to whether the government plans to sue the states to repeal the laws, as marijuana is still a schedule 1 substance under federal law (which trumps state law).
In order for the states to decide how to proceed in this case, they need to know how the federal government plans to respond to their decision to legalize marijuana. A significant amount of time has passed and the voters deserve a federal response in this case.