WASHINGTON (AP) -- Recent mass shootings like the massacre of first-graders and staffers at a Connecticut elementary school and the increasing deadliness of assault weapons make a ban on those firearms more urgent than ever, the Senate author of a proposal to prohibit them said Wednesday.
Sen. Dianne Feinstein, D-Calif., made the remark as the Senate Judiciary Committee held a hearing on her proposal, which would also bar ammunition magazines that can hold more than 10 rounds.
But the bruising, difficult path through Congress that the proposal will have was illustrated when the Judiciary panel's top Republican challenged the need for the assault weapons ban. Sen. Charles Grassley, R-Iowa, questioned the ban's constitutionality and said it would take the weapons away from people who use them for self-defense.
Further underscoring the roadblocks that gun control legislation faces in Congress, the chairman of the House Judiciary Committee said Wednesday that he opposes universal background checks for gun purchases, a central piece of President Barack Obama's plan for curbing gun violence. Rep. Bob Goodlatte, R-Va., told reporters that the proposal could lead to creation of a federal gun registry — which the Obama administration has said will not happen.
The hearing was the Senate's third since the Dec. 14 attack at Sandy Hook Elementary School in Newtown, Conn., that killed 20 students and six workers. The Judiciary panel could begin writing legislation as early as Thursday, but that session is likely to be delayed until next week.
Numerous relatives and neighbors of victims of Newtown, as well as other shootings at Aurora, Colo., and Virginia Tech filled the large hearing room.
At one point, Feinstein played a video showing how a bump fire slide, a piece of equipment added to an assault weapon, allows it to rapidly fire many rounds of ammunition, much as a machine gun would.
"The need for a federal ban has never been greater," Feinstein said.
Grassley expressed sympathy for gun violence victims, but said existing gun laws are not being adequately enforced, including background checks designed to prevent criminals from getting weapons.
"We should be skeptical about giving the Justice Department more laws to enforce" when it's not enforcing current ones, Grassley said.
Grassley said he believed Congress will eventually take action on boosting penalties for illegally trafficking guns, on more adequately keeping guns from people with mental problems, and encouraging states do a better job of reporting mental health records of potential gun buyers to the federal background check system.
At one point, Sen. Lindsey Graham, R-S.C., used his questioning of Milwaukee Police Chief Edward Flynn to argue that the current background check system is not being well enforced, since only a handful of the roughly 80,000 people annually who fail those checks are prosecuted for filing documents saying they qualify to own the weapons.
Uncharacteristially for a Senate hearing, Flynn interrupted the senator, saying, "I want to stop 76,000 people from buying guns illegally," a reference to the gun purchases that the background check system blocked last year. "That's what background check does."
His remark drew applause from spectators in the room.
Graham countered that "the best way to prevent crazy people" from getting weapons is to do a better job of identifying before they get weapons. He said today's laws must be enforced better, "rather than expanding them and creating a false sense of security."
Also slated to testify was Neil Heslin, whose 6-year-old son, Jesse, was among those slain at Newtown. Heslin has become an active proponent of gun control laws, including the assault weapons ban.
"It's a burden, it's more than a burden on me," Heslin said in an interview Tuesday as he and three dozen others — including other Newtown families and relatives of other mass shooting victims — arrived in Washington for two days of lobbying lawmakers. "But I have to do it for my little boy."
Across the Capitol on Wednesday, the House Education and Workforce Committee planned to hear from school safety experts and counselors about how to keep students safe.
Witnesses testifying to the Republican-controlled House panel were expected to emphasize the role of school resource officers — security professionals who are often armed and can double as informal counselors and liaisons to law enforcement. Those officers are commonplace in many schools and help officials develop safety plans.
Mo Canady, executive director of the National Association of School Resource Officers, was among those slated to testify, along with a school counselor and a school safety director.
Despite the raw emotion, Feinstein's effort to ban assault weapons is expected to fall short due to opposition by the National Rifle Association and many Republicans, plus wariness by moderate Democrats.
Feinstein's bill has attracted 21 co-sponsors, all Democrats. Including herself, it is sponsored by eight of the 10 Judiciary panel Democrats — precarious for a committee where Democrats outnumber Republicans 10-8. Democrats on the panel who haven't co-sponsored the measure include the chairman, Pat Leahy of Vermont, who said Monday he hadn't seen the bill.
President Barack Obama made bans on assault weapons and large capacity magazines key parts of the gun curbs he proposed in January in response to the Connecticut school massacre.
The cornerstone of his package is a call for universal background checks for gun buyers, some version of which seems to have a stronger chance of moving through Congress. Currently, only sales by federally licensed gun dealers require such checks, which are designed to prevent criminals and others from obtaining firearms.
Feinstein's bill would ban future sales of assault weapons and magazines carrying more than 10 rounds of ammunition but exempt those that already exist. It would bar sales, manufacturing and imports of semiautomatic rifles and pistols that can use detachable magazines and have threaded barrels or other military features. The measure specifically bans 157 firearms but excludes 2,258 others in an effort to avoid barring hunting and sporting weapons.
Feinstein, who helped create a 1994 assault weapons ban that expired in 2004, and other supporters cite studies showing use of the firearms in crimes diminished while the prohibition lasted. A 2004 report said the proportion of gun crimes involving assault weapons dropped by up to 72 percent in five cities studied.
Opponents cite data from that same study showing assault weapons were used in only 2 percent to 8 percent of gun crimes, arguing that a ban would have little impact. The study also estimated there were 1.5 million assault weapons owned privately in the U.S. in 1994, and an estimated 30 million high-capacity magazines as of 1999, which critics say means exempting them would diminish a ban's effect