On Tuesday, Holder told a meeting of state attorneys general he is examining policy options and international implications of the issue.
According to the U.S. attorney general, he is still in the process of reviewing the initiatives. Marijuana is illegal under federal law.
Holder's assessment could result in the federal government suing the states over the new laws. Alternatively, Holder could decide not to mount a court challenge. The Justice Department examination has been under way since shortly after last fall's elections. Washington and Colorado became the first states to pass laws legalizing the recreational use of marijuana.