WASHINGTON -- As lawmakers shaken by the shooting of a colleague return to the health care debate, an Associated Press-GfK poll finds raw feelings over President Barack Obama's overhaul have subsided.

Ahead of a vote on repeal in the GOP-led House this week, strong opposition to the law stands at 30 percent, close to the lowest level registered in AP-GfK surveys dating to September 2009.

The nation is divided over the law, but the strength and intensity of the opposition appear diminished. The law expands coverage to more than 30 million uninsured, and would require, for the first time, that most people in the United States carry health insurance.

The poll finds that 40 percent of those surveyed said they support the law, while 41 percent oppose it. Just after the November congressional elections, opposition stood at 47 percent and support was 38 percent.

As for repeal, only about one in four say they want to do away with the law completely. Among Republicans support for repeal has dropped sharply, from 61 percent after the elections to 49 percent now.

Also, 43 percent say they want the law changed so it does more to re-engineer the health care system. Fewer than one in five say it should be left as it is.

Congress stepped back last week to honor victims of the rampage in Tucson, Ariz., that left Rep. Gabrielle Giffords, D-Ariz., facing a long and uncertain recovery from a bullet through her brain.

House Republican leaders say they're working to keep this week's debate -- and expected vote Wednesday -- from degenerating into a shouting match, but it depends on the Democrats, too. Republicans want a thoughtful discussion about substantive policy differences, said Brad Dayspring, a spokesman for Rep. Eric Cantor, the No. 2 GOP leader. The AP-GfK poll was under way when the attack in Tucson took place Jan. 8.

Opposition to the law remains strongest among Republicans. Seventy-one percent of them say they're against it, as compared with 35 percent of independents and 19 percent of Democrats. Republicans won back control of the House partly on a promise to repeal what they dismissively term as "Obamacare."

The AP-GfK Poll was conducted Jan. 5-10 by GfK Roper Public Affairs and Corporate Communications. It involved landline and cell phone interviews with 1,001 adults nationwide, and has a margin of sampling error of plus or minus 4.2 percentage points.