"I think going to the public school kind of made me what I am today," Kelly said during a NASA interview. He filled the time between classes with baseball, swimming, track and football.

Winning a spot at the Merchant Marine Academy, Kelly, now 49, worked on a grain carrier ship as it inched its way across the Pacific. "I thought, 'Boy, this is way too slow,' " he said. "That's when I started thinking about flying airplanes in the Navy."

Years later, after flying the final mission of the space shuttle Endeavour, Kelly said, he realized that his Navy and NASA training had prepared him to help his wife after she was shot.

"I did see, you know, some parallels between what I had to deal with in flying airplanes and flying the space shuttle and what I had to deal with in handling this situation," Kelly told Piers Morgan in 2011. "I would think about these things in the context of, you know, what information do I have ... what kind of decision do I need to make, and do I need to make the decision right now, or can this wait?"

Giffords, 42, grew up in the same city where her life nearly ended on January 8, 2011. The daughter of a Tucson school board member, she attended Scripps College in California and later Cornell, where she studied regional planning. She entered politics in 2000, winning a seat in Arizona's legislature and later in the U.S. House of Representatives.

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