Several cautioned that the issue had raised complex legal and policy considerations — including enforcement priorities, litigation strategy and the impact of international antidrug treaties — that remain unresolved, and that no decision was imminent.

Several options are discussed in the Times article.

A more aggressive option is for the Justice Department to file lawsuits against the states to prevent them from setting up systems to regulate and tax marijuana, as the initiatives contemplated. If a court agrees that such regulations are pre-empted by federal ones, it will open the door to a broader ruling about whether the regulatory provisions can be “severed” from those eliminating state prohibitions — or whether the entire initiatives must be struck down.

Another potential avenue would be to cut off federal grants to the states unless their legislatures restored antimarijuana laws, said Gregory Katsas, who led the civil division of the Justice Department during the George W. Bush administration.