Kelly and Giffords met during a 2003 work trip to China. They reconnected again a year later after Kelly -- who had been married with two girls -- divorced his first wife. They started a long-distance relationship between Houston and Tucson, and by 2006, Giffords and Kelly were married.

The Tucson shooting didn't change Giffords' personality; it amplified it, Simon said. Giffords has relied on her resilience, Simon said, to recover from wounds that have left her with a brain injury, partial blindness and a paralyzed right arm. She resigned from Congress a year ago to focus on her recovery.

"Her speaking is really coming along," Simon said.

Kelly has spoken about some of the most personal ways that the Tucson attack has changed him. Until the shooting, he said, he hadn't been a "big believer in faith."

"I thought the world just spins, and the clock just ticks, and things happen for no particular reason," Kelly said.

'Willing to put herself out there'

The couple's visit to Newtown earlier this year may have revealed their lobbying strategy: more personal. Less public.

The media were not invited as Kelly and Giffords met privately with parents whose children had been shot to death by a 20-year-old armed with a military-style weapon and two handguns.

The "first couple that we spoke to, the dad took out his cell phone and showed us a picture of his daughter, and I just about lost it, just by looking at the picture," Kelly told ABC News. "It was just very tough, and it brought back a lot of memories about what that was like for us some two years ago."

"I have a lot of regard for her," said Pat Llodra, a Newtown community leader who also met with Kelly and Giffords. "She was harmed, and she was still willing to put herself out there to make a change."

Simon expects to see and hear a lot more from Giffords. "She and Mark intend to work together as a team," she said.

What Giffords and Kelly share with the Bradys is their movement toward activism through the power of their own personal tragedies.

Brady has held off reaching out to Giffords and Kelly out of respect for their privacy. "I would love to speak to them now and just thank them for stepping up to the plate and wanting to help on this issue."

They're both heroes, she said.

"None of us were activists until the shootings happened."

Sarah Brady didn't enter the gun control fray until four years after her husband had been wounded. That's when Jim Brady's injuries and the horror of seeing her 6-year-old son, Scott, accidentally handling a handgun crystallized her mission one night in 1985. "It just hit me like a ton of bricks," she said. "So I asked Jim if he felt comfortable with me speaking out, and he said, 'of course.'"

After that, the Bradys made it their business to be gun control activists.

Despite budgets that were just a fraction of the gun lobby's, the Bradys and their colleagues helped pass federal and state laws, including Maryland's 1988 ban on cheap handguns known as Saturday night specials, 1993's Brady Law requiring background checks on certain kinds of gun purchases and a ban on manufacturing and future sales of some military-style firearms, which lasted from 1994 to 2004.

Three decades after John Hinckley Jr. shot Reagan, Jim Brady and two others outside the Washington Hilton Hotel, Brady, now 72, has had a tough year, his wife said. "He no longer can stand. He has lost his sight, and he is in some pain. But his mind and everything else is perfect."

Lessons learned

The Bradys' victories may offer winning strategy ideas for Giffords and Kelly.

"Far be it for me to give them advice," said Sarah Brady, now 71. But she's found it helpful to "let members of Congress who are straddling the fence know that public opinion is with you. Make it an embarrassment if they don't do the right thing."

The Brady Law has kept deadly firearms out of the hands of more than 2 million people who failed background checks, according to Brady's group.

Giffords and Kelly say they want Congress to expand the law to require background checks for all gun buyers. Brady agrees.

"We can pass something very, very quickly in the area of background checks," Brady said. "But there are a lot of things that could derail it. With so much of the media everywhere and so many things going on all the time, none of us have the attention span we used to have to stay on one subject. If something new happens, then the discussion will move somewhere else. We've got to stay focused and stay on task and do it quickly."

Brady is optimistic that Congress will vote to expand background checks on firearms purchases. "I think it can be done," she said. "Do I think it's going to be done? I'm not sure. It's going to depend on people like Jim and me and Gabby and Mark."