The federal government resumed its bid to ban Oregon doctors from helping terminally ill patients commit suicide, filing papers Monday with an appeals court in an effort to strike down the only such law in the nation.

Attorney General John Ashcroft is seeking to sanction and perhaps hold Oregon doctors criminally liable if they prescribe lethal doses of medication, as the voter-approved Death With Dignity Act allows.

"The attorney general has permissibly concluded that suicide is not a legitimate medical purpose," Justice Department attorney Jonathan H. Levy wrote in the appeal filed at the 9th U.S. Circuit Court of Appeals.

A federal judge in Portland, Ore., blocked the Justice Department in April from punishing Oregon doctors -- such as stripping them of their ability to dispense medication if they prescribe lethal doses of medication to the terminally ill.

The case is a classic states' rights battle, with Oregon defending its assisted-suicide law against attacks from the Justice Department.

In a sharp rebuke to Ashcroft, Jones ruled in April that the Controlled Substances Act -- the federal law declaring what drugs doctors may prescribe -- does not give the federal government the power to say what is a legitimate medical practice.

Ashcroft first declared the federal government had such power on Nov. 6, 2001, and the government reiterated that point Monday, arguing the act "prohibits physicians from prescribing controlled substances except for legitimate medical purposes."

The government wrote Monday that Jones did not have such authority when he declared "the citizens of Oregon, through their democratic initiative process, have chosen to resolve the moral, legal and ethical debate on physician-assisted suicide for themselves by voting -- not once, but twice -- in favor of the Oregon act."

Oregon voters first approved the act in 1994 and overwhelmingly affirmed it again three years later when it was returned to the ballot following a failed legal challenge.

The law allows terminally ill patients with less than six months to live to request a lethal dose of drugs after two doctors confirm the diagnosis and judge the patient mentally competent to make the request.

Oregon Gov. John Kitzhaber, who is a physician, signed the law in 1998. Since then, Oregon has reported that at least 91 people have used the law to end their lives. Most of them suffered from cancer.

Ashcroft's Nov. 6 directive also banned any lethal prescriptions on grounds they did not qualify as medication under the federal Controlled Substances Act.

Oregon Attorney General Hardy Myers challenged Ashcroft in federal court last fall. Ashcroft's directive reversed a 1998 opinion by former Attorney General Janet Reno.

The state argues that regulating and licensing doctors generally has been the sole responsibility of the states, which license doctors to practice medicine. Oregon said Congress intended only to prevent illegal drug trafficking by doctors under the Controlled Substances Act, and it left any decisions about medical practice up to the states.

Myers spokesman Kevin Neely said Oregon vigorously would defend the will of state voters.

"The federal government doesn't have authority to say what is a legitimate medical purpose," Neely said.

Marc Spindelman, an Ohio State University College of Law scholar, isn't so sure about the state's argument. If Oregon's position is upheld, that would mean the states might be allowed to prohibit abortion, he said.

"If it's the case that states have the right to regulate medical practice, why then couldn't states regulate other medical practices, potentially, even including abortion?" Spindelman asked. "It's in conflict with the U.S. Supreme Court that said the states couldn't ban abortion."

Oregon has about a month before it must file opposition papers. The court has not said when it would hear the appeal.

Also pending before the San Francisco circuit court is an appeal from doctors challenging Justice Department sanctions -- including losing their ability to prescribe medication -- if they recommend patients use medical marijuana. California, Oregon and six other states allow sick patients to use marijuana with a doctor's recommendation.

The assisted suicide case is Oregon v. Ashcroft, 02-35587. The medical marijuana case is Conant v. Walters, 00-17222.