By Michael Tarm

The Associated Press

CHICAGO — Eight former Drug Enforcement Administration chiefs said today that the federal government needs to act now or it might lose the chance to nullify Washington’s law legalizing recreational marijuana use.

They also said the same about Colorado’s law, passed by voters the same election day that Washington’s voters approved an initiative last November.

The statement came on the same day a United Nations-based drug agency urged the U.S. government to challenge those laws, saying they violate international drug treaties.

The onetime DEA heads issued joint statements saying the Obama administration has reacted too slowly and should immediately sue to force the states to rescind the legislation.

One of the former DEA administrators, Peter Bensinger, told The Associated Press the day before that the more time that goes by, the harder it’ll be to stop the two states. Marijuana is illegal under federal law.

Bensinger, who lives in the Chicago area, said the government must immediately sue the states or risk creating “a domino effect” in which other states follow suit.

“My fear is that the Justice Department will do what they are doing now: do nothing and say nothing,” said Bensinger. “If they don’t act now, these laws will be fully implemented in a matter of months.”

The U.N. agency, the International Narcotics Control Board made its appeal in an annual drug report, calling on federal officials to act to “ensure full compliance with the international drug control treaties on its entire territory.”

U.S. Attorney General Eric Holder told a meeting of state attorneys general last week that he is still reviewing the laws but that his review is winding down. Asked Monday for a comment on the criticism from the former DEA administrators, Holder spokeswoman Allison Price would only say, “The Department of Justice is in the process of reviewing those initiatives.”

The department’s review has been under way since shortly after last fall’s elections. It could sue to block the states from issuing licenses to marijuana growers, processors and retail stores, on the grounds that doing so conflicts with federal drug law. Alternatively, Holder could decide not to mount a court challenge.

The ex-DEA heads are issuing the statements through the Florida-based Save Our Society from Drugs, a national group lobbying against legalization. One of the group’s spokesmen is based in Chicago.

The former DEA administrators are Bensinger, John Bartels, Robert Bonner, Thomas Constantine, Asa Hutchinson, John Lawn, Donnie Marshall and Francis Mullen. They served for both Republican and Democratic administrations.

Holder is scheduled to appear Wednesday before a U.S. Senate judiciary committee hearing. The former DEA chiefs want senators to question Holder on the legalization issue.

Advocates of legalization have welcomed Colorado’s and Washington’s new laws, arguing that criminalizing drugs creates serious though unintended social problems. The ex-DEA heads say they disagree with that view.

After votes last fall, Colorado and Washington became the first states to legalize marijuana’s recreational use — putting federal authorities in a quandary over how, or whether, to respond.

Washington state officials responsible for creating a regulated marijuana system have said they are moving forward with a timetable of issuing producer licenses by August.

Bensinger — who served as DEA administrator under Presidents Gerald Ford, Jimmy Carter and Ronald Reagan — said the supremacy of federal law over state law when it comes to drug laws isn’t in doubt.

“This is a no-brainer,” he said. “It is outrageous that a lawsuit hasn’t been filed in federal court yet.”

Others, however, said tough drug laws can sometimes be part of the problem.

The director of the Open Society Foundations’ Global Drug Policy Program, Kasia Malinowska-Sempruch, blamed repressive drug laws for millions of arrests and called on the United Nations General Assembly to reconsider its approach when it holds a special session on drugs in 2016.