But she has managed to remain popular, winning election three times in the Tucson-area congressional district by holding centrist positions, reaching out to constituents and bucking her party’s position on many issues as a key member of the "Blue Dog Coalition" Democrats.

She has been tough on border security, but supports comprehensive immigration reform. She voted for President Barack Obama’s stimulus and health care reforms, but pushed the administration to put armed National Guard troops on Arizona’s border with Mexico to stop drug and human smuggling.

On the Second Amendment, Giffords was among more than 300 members of Congress who signed a brief urging the Supreme Court to strike down a District of Columbia ban on handguns, which the court did in 2008.

In the wake of her November re-election — where she fended off a strong tea party challenger in a Republican year that saw two other Arizona Democrats swept from Congress — Giffords has been mentioned as a possible Democratic nominee in 2012 for the U.S. Senate seat held by Republican Jon Kyl or for the governor’s office in 2014. Kyl has not said whether he’ll run again.

"When you’re talking about a future gubernatorial race or anything else, when you’ve run three times in a Republican district in a state that still has a narrow Republican majority, she goes to the top of the list," said Don Bivens, state Democratic Party chairman.

Giffords, 40, a one-time Republican, became a Democrat in 2000 and won election to the Arizona House, where she served one term. In 2002, she became the youngest woman ever elected to the Arizona Senate and was re-elected in 2004, then stepped down in 2006 to try for the seat of retiring Republican Rep. Jim Kolbe.

Known as "Gabby," she won an easy victory by taking conservative positions for a Democrat in the district that had elected the moderate Kolbe 11 times — helped by the missteps of an ultraconservative Republican who failed even to win Kolbe’s endorsement. She was easily re-election in 2008 .

She maintained her popularity in her district — anchored by Tucson and swinging south toward conservative retirement communities like Green Valley and east to even more conservative Cochise County — by scheduling regular outreach meetings where she would meet constituents one-on-one. It was at just such a meeting in Tucson where she was shot Saturday.

Giffords "has been a very successful politician, a very successful representative" through an engaging personality and by being centrist on many issues, Kolbe said Saturday.

"I think she engages people. You have to work hard to not like Gabby Giffords," Kolbe said. "She would talk to anybody and meet with anybody."

She admitted in an October interview with The Associated Press that such events can sometimes be challenging.

"You know, the crazies on all sides, the people who come out, the planet earth people," she said following an appearance with Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, in Tucson where Mullen was questioned by a woman who wanted the army to start "building cities instead of destroying them."

"I’m glad this just doesn’t happen to me," she said with a laugh.

In March, her Tucson office was vandalized a few hours after the House vote to approve the health care law, with someone either kicking or shooting out a glass door and window. In an interview after the vandalism, Giffords referred to the animosity against her by conservatives.

Giffords met astronaut Mark E. Kelly, who has piloted space shuttles Endeavour and Discovery, in 2003 while they were serving on a committee in China. They were married in January 2007, while Giffords served on the House Science and Technology space subcommittee. The couple have no children together; Kelly has two daughters.

Giffords began holding "Congress on Your Corner" events like Saturday’s in 2006, when she and other Democratic freshman were encouraged by their national leadership to meet directly with their constituents.

Under the format used by Giffords, people lined up and spoke one at a time directly with the congresswoman and her staff about whatever they wanted, such as requests for assistance with federal agencies or concerns about issues.

Giffords worked hard to win moderate Republicans and independents in her district, all the while knowing that her votes against some of her leadership’s priorities irked leftist Democrats.

"As a Democrat in a Republican district, the party registration doesn’t normally favor a member of the Democratic Party," Giffords told the AP in October. "I believe in continuing to appeal to the moderate Republicans, engaging the independents, and turning out the Democrats.

"A lot of the strong Democratic activists, the far, far left, aren’t happy with me," she said. "They don’t the fact that that I’m a Blue Dog and really push fiscal responsibility and deficit reforms. I’ve voted against my leadership."

Giffords was one of three 2010 candidates who received $2,400 campaign contributions from MSNBC’s Keith Olberman, resulting in a suspension for the prime-time host.

Former state Sen. Tim Bee, her 2008 challenger, was at the hospital in Tucson Saturday waiting for word on his longtime friend’s condition. The two have known each other since they were kindergarten classmates.

"As a friend, Gabby is just a very kind person, very gracious," Bee said. "She is the essence of someone raised in southern Arizona."

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Associated Press writer Terry Tang contributed from Tucson.