US lawmakers approved a Democratic bill Thursday that would ban assault weapons and high-capacity gun magazines, in a party line vote three months to the day after the Newtown school massacre.
The Senate Judiciary Committee voted 10-8 for the measure. But despite President Barack Obama's backing, the ban is seen by many as the most problematic element in the president's push to reduce weapons violence by tightening up Americans' easy access to firearms.
"These weapons of war, when combined with high-capacity magazines, have one purpose: to inflict maximum damage as quickly as possible," Obama said in a statement welcoming the vote.
"They are designed for the battlefield, and they have no place on our streets, in our schools, or threatening our law enforcement officers."
He urged the full Senate and the House of Representatives to take up the proposal.
The assault weapons measure -- as well as three other items approved earlier in the package of proposed gun reforms -- would result in the most substantial change to US gun legislation in a generation.
But the measures face an uphill battle, meeting with stiff opposition not just from Obama's Republican foes in Congress, but from many conservative-leaning Democrats as well.
The White House and Congress have zeroed in on potential measures to reduce gun violence in the wake of the December 14 massacre in Newtown, Connecticut that saw a gunman kill 20 young children and six adults before taking his own life at an elementary school.
The semi-automatic Bushmaster XM-15 rifle, the weapon used during the assault by accused gunman Adam Lanza, is the same sort of high-powered, automatic firearm that would be prohibited if the bill were to become law.
Senator Dianne Feinstein, one of the most ardent advocates for the assault weapons bill, and the author of the original law that was in force from 1994 to 2004, during committee debate decried them as "weapons of war."
The California Democrat pointed out that there are many other types of firearms that Americans are allowed to own for sport or self-protection without having to rely on assault weapons.
"Do they need a bazooka? Do they need other high-powered weapons, weapons that military people use to kill in close combat? I don't think so," she said during one particularly heated exchange with a Republican colleague.
But Republican Senator John Cornyn of Texas said that he, along with like-minded lawmakers and many members of the US public, believe that the gun ownership rights enshrined in the US Constitution give Americans the right to pack as much firepower as they choose.
"If the criminal element is going to be using weapons like this, why would you deny for defensive purposes otherwise law abiding citizens to be able to use an equivalent firepower to defend themselves?" Cornyn said.
The committee in recent days passed a gun-trafficking bill that would toughen penalties against people who purchase firearms for others who are not allowed to own weapons.
It also signed off on a measure to boost funding for school security and another tightening up of background checks on would-be gun purchasers.
The proposed assault weapons ban approved Thursday is a revamped version of a law that was allowed to lapse in 2004.
But that ban -- along with the universal background checks and other tightened gun regulations -- is vehemently opposed by most Republicans, and Democrats have struggled to find any GOP lawmakers willing to sign on.
The gun reform bill would need 60 votes to overcome Republican obstruction in the 100-seat Senate. Democrats hold 55 seats so they would need at least five Republicans to go along.
The bill then faces an even tougher road finding sufficient support for passage in the Republican-held US House of Representatives.