Late last week the Justice Department said that it will not challenge state laws that legalize marijuana, focusing instead on serious trafficking cases.

Under the new guidelines, issued by Deputy Attorney General James Cole, federal prosecutors are required to focus on eight enforcement priorities, including preventing marijuana distribution to minors, preventing drugged driving, stopping drug trafficking by gangs and cartels and forbidding the cultivation of marijuana on public lands.

The new guidelines have been months in the making and took on some urgency after citizens legalized pot in Colorado and Washington last fall. Nineteen states and the District of Columbia allow some legal use of marijuana, primarily for medicinal purposes.

The new guidelines don't change federal money laundering rules, which means that some large banks may still be leery of doing business with marijuana producers and sellers. However, Justice Department officials said there is some leeway for banks to provide services to such businesses, so long as they don't violate the eight priorities being assigned to federal prosecutors.

"We received good news this morning when Attorney General Eric Holder told the governor the federal government would not pre-empt Washington and Colorado as the states implement a highly regulated legalized market for marijuana," Washington Gov. Jay Inslee and Attorney General Bob Ferguson said in a statement.