Former congresswoman Gabrielle Giffords (D-Ariz.) urged Congress to act on gun violence during a Senate hearing Wednesday. Giffords was shot and seriously injured two years ago while meeting with constituents in Tucson. (JulieAnn McKellogg/The Washington Post)

She spoke just 72 words, reading slowly and carefully from a lined sheet of paper where a speech therapist had transcribed her thoughts. One of the many things former House member Gab­rielle Giffords has lost is the congressional luxury of being long-winded.

“You must act. Be bold. Be courageous,” Giffords testified Wednesday in her first formal ­remarks on Capitol Hill since a shooting that nearly killed her two years ago. “Americans are counting on you.”

Giffords (D-Ariz.) was the first witness called by the Senate Judiciary Committee on Wednesday in a hearing that served as the congressional kickoff for a bitter fight about guns.

Other witnesses included her husband, former astronaut Mark Kelly, who has joined her in a push to tighten gun laws. And at the other end of the witness table — and on the other side of the issue — was Wayne LaPierre, the National Rifle Association’s articulate, combative spokesman in Washington.

Four hours later, a lot had been said and very little had been settled. The memory of Giffords’s appearance gradually lost its solemn hold on the participants. At one point, a female gun rights advocate told a Democratic senator that he could not understand the appeal of a high-capacity ammunition magazine because he is “a large man” who doesn’t feel as vulnerable as a woman.

Sen. Richard Blumenthal (D-Conn.) says he “may be naive” but believes that tougher gun regulations will be enacted. He also says the memory of the Newtown shootings should be kept fresh as the law is written. (The Fold/The Washington Post)

But by the end, one thing seemed clearer: A consensus is emerging among lawmakers for an expansion of background checks for gun buyers, a proposal with far more bipartisan support than a reinstatement of the federal assault-weapons ban.

“Universal background checks is a proven, effective step we can take to reduce gun violence,” Sen. Charles E. Schumer (D-N.Y.) said at the hearing. “And I believe it has a good chance of passing.”

The purpose of the hearing was to shape gun legislation that can pass a splintered Congress. Committee Chairman Patrick J. Leahy (D-Vt.) said he expects the panel to craft a bill by next month.

Schumer has led the charge on mandating background checks for all firearms purchases, ending an exemption for sales at gun shows.

Also Wednesday, Sens. Kirsten Gillibrand (D-N.Y.) and Mark Kirk (R-Ill.) announced a new bipartisan measure to make gun trafficking a federal crime.

The hearing was a quiet — and mainly polite — discussion of violence.

Opponents of gun control told stories of homeowners shooting intruders in terrified self-defense. Supporters talked about the shooting rampage in Newtown, Conn., that left 20 elementary school students, six school staffers, the gunman and his mother dead in December. And they noted more recent violence: a shooting in Chicago on Tuesday that killed a 15-year-old girl who had come to Washington during the inaugural weekend, and a shooting Wednesday in Phoenix that injured at least three at an office building; it happened during the hearing.

The forum began with reminders of Jan. 8, 2011, when Jared Lee Loughner shot Giffords and 18 others at an event in a Tucson parking lot. She survived, partially blind and paralyzed in her right arm. Six in the crowd died.

“Speaking is difficult. But I need to say something important,” Giffords said, after walking through the packed, but nearly silent, hearing room to her seat. Friends said she had practiced her remarks again and again. “Violence is a big problem. Too many children are dying. Too many children. We must do something.”

When Giffords finished, Kelly guided her out a back door. She watched some of the hearing on television, and the couple later met with President Obama in the Oval Office.

After she left, Giffords’s name was invoked more than 40 times, and the hearing focused on her charge: how, or whether, to do something now.

Kelly and several Democrats on the committee advocated expanding background checks so that they cover all gun purchases. But the NRA’s LaPierre said such a strategy would accomplish little.

“So, we’re going to make all those law-abiding people go through the system, and then we aren’t going to prosecute any of the bad guys if they do catch one. And it — none of it makes any sense in the real world,” he said.

At that point, Leahy cut La­Pierre off, because the time for that period of questioning had expired. The next senator up was Richard J. Durbin (D-Ill.), who challenged LaPierre.

“Mr. LaPierre, that’s the point. The criminals won’t go to purchase the guns because there will be a background check,” Durbin said. “We’ll stop them from the original purchase. You miss that point completely.”

At another point, Leahy noted that LaPierre had supported universal background checks when he testified at a similar House hearing in 1999.

Kelly also discussed the idea of limiting the size of ammunition magazines. He said Loughner had carried a 33-round magazine and was stopped only when he paused to reload and fumbled a new magazine. What if, Kelly asked, he could have carried only a 10-round magazine? Might the rampage have ended sooner?

But Sen. Lindsey O. Graham (R-S.C.) asked if he was “unreasonable” for not supporting a ban on semiautomatic weapons or a limit on magazine capacity.

Graham cited a recent incident in which a Georgia woman used a six-shot pistol to shoot a home invader. The man was hit five times, Graham said, but was still able to flee the scene.

Turning to Kelly, Graham asked: “Put your family member in that situation. Would I be a reasonable American to want my family to have the 15-round magazine in a semiautomatic weapon to make sure that if there’s two intruders, she doesn’t run out of bullets? Am I an unreasonable person for saying that in that situation, the 15-round magazine makes sense?”

Kelly did not respond aloud. Graham gave his own answer: “Well, I’ll say I don’t believe I am.”

Relatively little support was expressed for reinstating the assault-weapons ban that expired in 2004. Sen. Dianne Feinstein (D-Calif.) has filed a bill to do that, but she spent little time discussing it at the hearing.

She did not question LaPierre when it was her turn to address witnesses, but she acknowledged their history of sparring at congressional hearings and on television about gun-control proposals. “It’s good to see you again,” she said to LaPierre. “We tangled — what was it? — 18 years ago. You look pretty good.”

Feinstein’s proposed ban was challenged by freshman Sen. Ted Cruz (R-Tex.), who used charts and props to argue that her bill is written illogically, banning some rifles and permitting others that are nearly identical.

One of the more vivid exchanges involved Sen. Sheldon Whitehouse (D-R.I.) and Gayle Trotter, a conservative lawyer. Trotter pushed to keep assault weapons and high-capacity magazines available, arguing that they are essential to women in particular: Such guns are more intimidating to potential attackers, she said, and easier for a smaller person to wield. She cast the issue in language familiar from the abortion debate, talking about “our Second Amendment right to choose to defend yourself.”

In response, Whitehouse said he did not believe that a woman would need a 100-round magazine for self-defense.

Trotter challenged him, her voice rising: “How can you say that? . . . You are a large man.”

“A tall — tall man,” she continued, speaking to Whitehouse. “You are not a young mother who has a young child with her. And I am passionate about this position. Because you cannot understand. You are not a woman stuck in her house having to defend her children, not able to leave her child, not able to seek safety, on the phone with 911. And she cannot get the police there fast enough to protect her child.”

Citing the clock, Leahy cut off their discussion.

Philip Rucker, Sari Horwitz and Julie Tate contributed to this report.