WASHINGTON -- Two years ago, Gabrielle Giffords became an unwitting symbol of the scourge of gun violence in the United States when a would-be assassin shot the Arizona congresswoman in the head, killing six others in the process.

Giffords, after all, a Democratic lawmaker, had defended the constitutionally enshrined right of Americans to bear arms. She and her husband, astronaut Mark Kelly, even own two guns themselves, locked in a safe in their home.

But that was then, this is now -- America in the aftermath of yet another mass shooting, one that took a particularly terrible toll.

Twenty first grade pupils were among the 26 victims in small-town Connecticut last month, gunned down by a troubled young man toting his well-heeled mother's assault rifle.

"America has seen an astounding 11 mass shootings since a madman used a semiautomatic pistol with an extended ammunition clip to shoot me and kill six others," Giffords and Kelly wrote Tuesday in an op-ed in USA Today announcing their new organization aimed at pushing for stricter gun control.

"This country is known for using its determination and ingenuity to solve problems, big and small.... But when it comes to protecting our communities from gun violence, we're not even trying -- and for the worst of reasons."

Exactly two years since the bloodshed in a Tucson parking lot, the couple has announced the formation of Americans for Responsible Solutions, a group that hopes to loosen the iron grip the powerful National Rifle Association has had on U.S. Congress for the past three decades.

The couple is calling for donations to help "encourage elected officials to stand up for solutions to prevent gun violence and protect responsible gun ownership."

"Special interests purporting to represent gun owners but really advancing the interests of an ideological fringe have used big money and influence to cow Congress into submission," they wrote.

"Rather than working to find the balance between our rights and the regulation of a dangerous product, these groups have cast simple protections for our communities as existential threats to individual liberties. Rather than conducting a dialogue, they threaten those who divert from their orthodoxy with political extinction."

Giffords and Kelly are pushing for a ban on semi-automatic weapons and high-capacity ammunition magazines.

Their call to action is in apparent lockstep with the White House. The U.S. capital has been abuzz for weeks about efforts in the works by the Obama administration to deliver a body blow to the NRA by bringing together law enforcement officials, business groups and religious leaders to push for comprehensive gun control.

The timing appears to be right in terms of public opinion. In the wake of the Newtown shooting, polls are suggesting the majority of Americans support tougher gun control laws, a dramatic turnaround from just a year ago.

A recent CNN survey found that 94 per cent of Americans support background checks for those buying guns, while 61 per cent back a ban on semi-automatic assault guns and high-capacity magazine clips.

President Barack Obama has tapped Vice-President Joe Biden to helm an administration-wide task force on gun violence; the president wants proposals on his desk by the end of the month.

Biden, a vocal gun control advocate during his 30 years in the U.S. Senate, is scheduled to meet Wednesday with gun violence victims' groups and gun safety organizations.

On Thursday, Biden will sit down with gun ownership groups, including the NRA, and advocates for sportsmen. Meetings are also said to be in the works with representatives from the entertainment and video game industries.

It's hardly smooth sailing ahead for gun control advocates hoping for meaningful legislation, however.

One newly elected senator, Democrat Heidi Heitkamp, became a target of gun control groups this weekend when she dismissed as "extreme" some proposals being considered by the White House, including the ban on assault rifles and high-capacity ammunition magazines.

The North Dakota senator has been given a grade of "A" from the NRA, which ranks politicians according to their positions on gun rights.

Indeed, a number of Democratic senators in traditionally Republican states are up for re-election in less than two years and may be reluctant to flout the NRA. That means Democrats could lack the votes to pass gun control legislation in the Senate while the House of Representatives remains firmly under Republican control.

The hot-button politics of the issue were on full display last week, when Giffords and Kelly visited Newtown to meet with victims' families and local and state officials to discuss gun control legislation and mental health identification and treatment.

Their visit didn't go over too well with DebraLee Hovey, the No. 2 Republican in the state of Connecticut. Hovey took to Facebook to post the message: "Gabby Gifford stay out of my towns!" and accused Giffords of having "pure political motives."

She later apologized, but said her community was "very sensitive to the potential for this event to be exploited for political purposes. This is what I wish to avoid."

Kelly, meantime, has been going head-to-head with the NRA, dismissing its insistence that further arming citizens could help curtail mass shootings.

"The only thing that stops a bad guy with a gun is a good guy with a gun," Wayne LaPierre, NRA's executive vice president, said in a surreal news conference a week following the Connecticut shootings.

That's simply not the case, Kelly said in a recent interview with ABC. Such a "good guy" almost gunned down the man who finally restrained gunman Jared Loughner on the day Giffords was shot, he pointed out.

"The one who eventually wrestled him to the ground was almost killed himself by a good guy with a gun, so I don't really buy that argument," Kelly said.

A coalition of mayors has released an ad featuring the mother of Christina-Taylor Green, the nine-year-old girl killed that day.

In the TV spot, Roxanna Green asks lawmakers: "When will you find the courage to stand up to the gun lobby? Whose child has to die next?"