Eight weeks after the massacre of 20 Connecticut first-graders, a ban on the kind of semi-automatic rifle used by the killer remains elusive -- if not impossible.

Such a ban became a rallying cry for victims' families, advocacy groups and politicians supporting tougher gun laws in the emotional aftermath of the Newtown shootings in December.

President Barack Obama still calls for updating a 1994 assault weapons ban that expired 10 years later as part of his package of steps intended to reduce chronic gun violence in America, especially in major cities.

However, fierce opposition by the powerful National Rifle Association and millions of American gun owners has shifted debate away from prohibiting specific weapons to making it harder for criminals, terrorists and the mentally ill to obtain guns.

Along with a renewed ban on semi-automatic weapons, Obama also wants to limit magazine clips to 10 rounds, expand background checks to all gun sales, crack down on gun trafficking, and strengthen efforts to prevent firearms from falling into the wrong hands.

The multi-faceted proposal provided Congress with options on legislation, enhancing chances of passing some provisions, said Lanae Erickson Hatalsky, director of social policy and politics at Third Way, a Washington think tank that proposes policy compromises on major issues.

While her group supports a renewed ban on military style weapons, Erickson Hatalsky said "political reality" dictated a different approach.

"Keeping guns out of the wrong hands is not only more politically palatable but also more effective to stop gun violence," she explained.

That strategy reflects "an understanding of gun crime in the country," she added.

Opinion polls back up her assertion.

A Quinnipiac University survey released Thursday showed that 92% of respondents support expanding background checks to all gun sales. In households with guns, support was 91%.

However, a majority of households with guns opposed a renewed ban on semi-automatic weapons, while the full survey showed 56% of respondents backed the provision.

The poll also found that 46% of respondents believe the NRA better reflects their views on guns, compared to 43% for Obama.

Diverse views in America

Obama acknowledged on Thursday that Americans have diverse views on the issue, depending on where they grew up and how they live.

"There are different realities and we have to respect them," he told House Democrats at their policy retreat, noting rural hunters and urban dwellers come from distinct gun cultures.

At the same time, the president called for action, saying "there are commonsense steps we can take and build a consensus around, and we cannot shy away from taking them."

Earlier this week, White House spokesman Jay Carney made clear that the goal was progress on reducing gun violence, rather than any specific provision.

Carney called proposals backed by legislators from both parties "the first progress we've seen in many, many years dealing with gun violence." But none of the measures he mentioned -- expanded background checks, cracking down on gun trafficking, criminalizing "straw" purchases in which legal buyers obtain weapons for those unable to do so -- included a new ban on semi-automatic weapons.

NRA President Bob Keene said he expected few substantive changes in law because "people are smarter than politicians," which means "common sense ultimately prevails."

"They hope that they can use emotion to achieve an anti-firearms agenda that they haven't been able to achieve in the past," Keene told a recent Christian Science Monitor breakfast event.

"I am convinced that as these things are discussed, that we're going to come out about where we have come out in the past," he added.

His organization keeps a scorecard for each Washington legislator on gun issues, and spends millions on campaign contributions to favored candidates.

In the nearly two months since the Newtown shootings, Obama and the White House have sought to maintain public attention on the issue.

Vice President Joe Biden will take part in a roundtable discussion on gun violence on Monday in Philadelphia.