WASHINGTON — Former Rep. Gabrielle Giffords made a surprise appearance Wednesday at the Senate Judiciary Committee’s hearing on gun violence, urging lawmakers to “be bold, be courageous.”

The four-hour hearing featured testimony from big players in the gun control debate, including Giffords’ husband, former astronaut Mark Kelly, and National Rifle Association CEO Wayne LaPierre.

Giffords, who was seriously injured by a gunshot to the head at a campaign event in Arizona two years ago, addressed the senators and a hushed crowd.  Many stood and craned their necks to see her as she entered the room. Giffords said that although the simple act of talking is still difficult for her, “I need to say something important.

“Too many children are dying …” she told committee members with a slow but firm cadence. “We must do something. It will be hard, but the time is now. You must act. Be bold, be courageous. Americans are counting on you.”

Senators and witnesses on both sides of the issue said they respected the Second Amendment and looked to defend it, but the ways that each side promised to do that differed.

Democratic senators, along with Kelly and Baltimore Chief of Police Jim Johnson, cited a variety of legislative measures, like universal background checks, bans on some semi-automatic weapons, restrictions on high-capacity magazines and mental health reform.

In arguing against new gun control laws, LaPierre was joined Republican senators and fellow witnesses Gayle Trotter, a senior fellow at the Independent Women’s Forum and David Kopel, a Denver University adjunct professor of advanced constitutional law.

LaPierre laid out the NRA’s solutions as armed security personnel in schools, reforming the country’s  mental health programs and more federal gun prosecutions. The NRA’s CEO railed against the mostly Democratic legislative efforts, which he said often impact the average citizen instead of criminals who seek to illegally obtain weapons.

“If you’re in the elite you get bodyguards … criminals don’t obey laws anyway, and in the middle, we have hardworking, law-abiding Americans,” LaPierre said. “…That’s why these bills are so troubling.”

Kelly, a retired Navy captain,  disagreed with many of LaPierre’s points and used his knowledge of Giffords’ shooter to talk about issues such as background checks and bans on large magazines. Kelly and Giffords – both gun owners — recently started a gun control advocacy organization, Americans for Responsible Solutions. Kelly described the group as “pro-gun ownership, anti-gun violence.”

Speaking in a packed hearing room, Kelly made a poignant appeal for banning high-capacity magazines, such as the one suspect Jared Lee Loughner is accused of using in the Giffords shooting in January 2011. Loughner, who allegedly used a 33-round magazine, hit Giffords with the first bullet, Kelly said. The thirteenth round hit Christina-Taylor Green, a nine-year old girl and the shooting’s youngest victim.

By Kelly’s account, when Loughner attempted to replace one magazine with another, he dropped it, interrupting the fire and giving a bystander an opportunity to grab it and stop the shooting. If the law had only permitted Loughner to purchase a 10-round magazine, Kelly said, Green would still be alive.

“I certainly would give up my right to own a high-capacity magazine today to bring that young girl back,” he said.

Judiciary Chairman Patrick Leahy, D-Vt., who echoed many of Kelly’s comments about restrictions, spoke of his experiences as “a responsible gun owner and someone who cherishes all of our constitutional rights.” He called on his committee to work to “build consensus around common sense solutions” in the hearing that was at times tense.

An issue of particular contention was closing the gun show loophole, which allows people to purchase guns without a background check if the sale is  from a private seller at a show. LaPierre said his problem with expanding background checks was that they “will never be ‘universal,’ because criminals will never submit to them.”

“Mr. LaPierre, that’s the point,” Sen. Richard Durbin, D-Ill., said in a wrought exchange with the NRA leader to the applause and laughter of some audience members. “Criminals won’t go to buy the guns because there will be a background check.”

What direction the nation should take in regulating gun ownership and purchases was not clear through the course of the  hearing, but in his closing remarks, Leahy said that the committee has a mandate to move forward with legislation.

“You know, I live an hour’s drive from another country, Canada,” he said. “I don’t see the same kind of problem there. I want to find out how we can stop what is happening. I believe there should be some areas of agreement, and I hope the committee can get together to mark up legislation next month — this month is virtually over — and then take it to the floor.”