Why Supreme Court is asking the federal government about marijuana

In May 2015, the US Supreme Court asked the federal government for advice.
On Wednesday, Solicitor General Donald B. Verrilli filed his brief on the increasingly tricky issue of marijuana legalization, technically outlawed as a Schedule I substance under the federal Controlled Substance Act.
Hearing the case, "essentially that one state's laws make it more likely that third parties will violate federal and state law in another state - would represent a substantial and unwarranted expansion of this Court's" jurisdiction,  Verrilli told the High Court.
The state marijuana quandary has existed since at least 2009 , when the Department of Justice said that prosecuting drug use legal under state laws would not be a priority.
"The state of Colorado has created a dangerous gap in the federal drug control system enacted by the Unites States Congress," Nebraska Assistant Attorney General Ryan Post told the Court.