President Obama has become quite the drug warrior.

Last month, his Bureau of Alcohol, Tobacco, Firearms and Explosives issued a memo that stated that it is unlawful for anyone with a state-issued medical marijuana card to possess a gun or ammunition. This month, four U.S. attorneys in California announced that they are escalating prosecution of medical marijuana clubs by going after the assets of their landlords and property owners.

As a senator and presidential candidate, Obama supported states' rights on medical marijuana. In 2008, campaign spokesman Ben LaBolt told me Obama "believes that states and local governments are best positioned to strike the balance between making sure that these policies are not abused for recreational drug use and making sure that doctors and their patients can safely access pain relief."

When he was first in office, it looked as if Obama would do as he had said. Drug war opponents were pleasantly surprised in 2009 when a Department of Justice memo advised U.S. attorneys not to "focus federal resources" on "individuals with cancer or other serious illnesses who use marijuana as part of a recommended treatment regimen" consistent with state law or their caregivers.

But this year, charges Ethan Nadelmann, executive director of the anti-drug-war Drug Policy Alliance, Obama seems controlled by "over-zealous prosecutors and anti-marijuana ideologues."

Now I believe marijuana should be legal, and not simply for medical use.

But I also recognize that federal law trumps state law. Many marijuana suppliers hide behind the mantle of palliative care to profit from recreational use and abuse. It must drive prosecutors nuts to watch what are basically criminal enterprises cash in by taking legal cover under state law while flouting federal law. Washington could remedy that by legalizing marijuana.

But when U.S. attorneys in California send out dozens of letters threatening landowners and lien holders with the seizure of their property and assets, they're not going after the drug trade. They are using the full force of the federal government to threaten people whose crime is renting, not breaking federal criminal law. Make that renting to businesses allowed under state law.

"Although our initial efforts in the Northern District focus on only certain marijuana stores," San Francisco's U.S. Attorney Melinda Haag explained in a statement, "we will almost certainly be taking action against others. None are immune from action by the federal government."

You don't have to sell or distribute marijuana to have a target on your back. It's easier to go after landlords. Prosecutors have to prove defendants guilty beyond reasonable doubt in criminal court, but asset forfeiture law allows the government to seize property in civil court.

U.S. Attorney Laura Duffy of Southern California has said that she is ready to go after newspapers, radio stations and other outlets that run ads for medical marijuana shops because federal law targets those who place ads for an illegal substance. Duffy told California Watch, "I am willing to read (the law) expansively, and if a court wants to more narrowly define it, that would be up to the court."

I should note that The Chronicle has run such ads.

Nadelmann told me that he now thinks Obama today is as bad as his predecessors when it comes to the drug war.

One could argue that Obama is worse; President George W. Bush didn't go after newspapers.

In 1996, Californians voted to legalize medical marijuana; as of today, 15 other states have followed suit. In 2008, Obama respected states' rights. In 2011, his administration is ready to bulldoze its 2009 advisory that the feds not pick on sick people.

Sen. Jon Tester, D-Mont., protested that the ATF memo is unacceptable because "law-abiding citizens would be stripped of their Second Amendment rights simply because they hold a state-issued card authorizing the possession and use of marijuana for medicinal purposes."

Nadelmann cannot understand why the Obama Justice Department is willing to alienate real estate agents, property owners, gun owners and the Democratic base. "Typically, as an advocate," he said, "your best opportunities emerge when the other side overreaches."

Bingo.

I've talked to folks in law enforcement who stew over medical marijuana businesses serving as fronts for criminal enterprises. But now the administration is threatening to go after cancer patients who own guns and small businesses that rent to marijuana shops. They are going after people whom they do not consider to be criminals.

That's why some states decided to pass medical marijuana laws in the first place. They do not want the heavy boot of federal law enforcement stomping on the wrong people.