The Republican-controlled House yesterday voted to ban physician-assisted suicide, its strongest effort yet to turn back a fledgling social movement aimed at ending the suffering of terminally ill patients.

The "Pain Relief Promotion Act" includes a host of uncontroversial provisions encouraging doctors to ease the pain of dying patients without killing them, but there was fierce debate over the bill's effort to invalidate Oregon's groundbreaking law permitting physician-assisted suicide.

In the end, the House approved the bill 271 to 156, and Senate leaders say they have the votes to pass the measure despite a threatened filibuster from Sen. Ron Wyden (D-Ore.).

The Oregon law, approved two years ago, provided the first official sanction for the notion that doctors could assist in making suicide as painless as possible; California's legislature is considering a similar bill and Maine will hold a referendum on euthanasia next year. The assisted-suicide debate has intensified over the last decade--fueled in part by Jack Kevorkian, who helped more than 100 Americans kill themselves before he was jailed last year--and lawmakers said yesterday they were sending a strong signal of their disapproval of such efforts.

"We're drawing a bright line here. We're saying that physicians should be healers, not agents of death," said Rep. Charles T. Canady (R-Fla.), one of the bill's sponsors.

Supporters of the Oregon approach warn that by criminalizing physician-assisted suicide, Congress would empower Drug Enforcement Administration agents to determine whether physicians who prescribe painkillers are trying to kill patients, and would scare doctors away from palliative care out of fear of prosecution.

"The Death With Dignity law has made Oregon the nation's leader in end-of-life care," said Hannah Davidson, director of the Oregon Death With Dignity Legal Defense and Education Center. "This new federal law would undermine all the advances we've made."

The Supreme Court has said there is no constitutional right to physician-assisted suicide--and left it up to government to either ban it or legalize it. Supporters of the House bill argued that the Controlled Substances Act of 1970 gave the federal government the responsibility to regulate painkillers, but yesterday's vote was the latest in a series of efforts by the GOP-controlled Congress to supersede state laws it finds distasteful.

President Clinton has said he opposes physician-assisted suicide, but administration officials noted they have reservations about the House bill, saying it raises troubling states' rights issues and practical questions about how it would be enforced. The Justice Department has described it as an unwarranted intrusion on state prerogatives.

On the House floor yesterday, the bill's opponents repeatedly complained that despite the frequent rhetorical nods to states' rights on Capitol Hill, Congress was deciding once again that it knows best.

"It's ironic that the Republicans who always talk about sending power out of Washington are voting to overturn a state law," said Rep. Nancy L. Johnson (R-Conn.), one of 20 Republicans who opposed the bill. "It's unfortunate that we keep trying to impose our views on states."

Yesterday's vote began a new chapter in the turbulent history of Oregon's "Death With Dignity" law, which went into effect on Oct. 27, 1997, after two successful statewide referendums and several court challenges. The law allows physicians to prescribe--but not administer--lethal doses of drugs for patients who have less than six months to live, are deemed mentally competent, and choose death voluntarily in front of witnesses.

Over the last two years, Oregon has had about 30 assisted suicides. But its doctors now lead the nation in the use of medical morphine, its hospitals have the nation's lowest mortality rates, and its hospice rates have soared. Supporters of the House's "pain relief promotion" measure noted that five states have passed similar bills--and all five have had significant increases in the use of medical morphine to relieve suffering.

Last year, the House rejected a simple assisted-suicide ban, but this year, the authors tried to draw a sharp distinction between the use of painkillers to ease pain and the use of painkillers to cause death. The new bill, for example, gives doctors more leeway to prescribe narcotics to reduce suffering in seriously ill patients. There were some divisions within the medical community over the bill, but it did have the support of the American Medical Association.

"It comes down to this: Do we want to empower our doctors to intentionally kill patients?" asked Rep. Henry J. Hyde (R-Ill.), the bill's chief sponsor. "We believe doctors should help people cope with the pain and terror of death, not thrust death upon them."

For all the passionate disagreements over assisted suicide and the sanctity of life, just about every House member seemed to agree that doctors still need more leeway to prescribe painkillers. Yesterday, many of them told stories about the suffering of their own loved ones, although they all drew different lessons from their experiences.

Rep. Greg Walden (R-Ore.) grimly recalled watching "the life drain away from my young son," but argued that his state's voters should be entitled to their own opinions about assisted suicide. But Rep. Spencer Bachus (R-Ala.) remembered how a doctor gave his grandmother one night to live, three years before her death--a stark example of why he supported the bill.