Another grass-roots lobbying push for gun control legislation is being staged today by former Rep. Gabrielle Giffords and her husband, Mark Kelly. But there is no sign at all that the Arizona Democrat and her former astronaut husband will gain any new support at the Capitol.

The couple are delivering a blunt letter to every member of Congress signed by 100,000 members of American for Responsible Solutions, the advocacy group they started after the Giffords resigned in January 2012, a year after she was severely wounded and six others were shot dead at a constituent meet-and-great in Tucson.

“We have disturbing problems — gun crime, mental illness, and the easy access that dangerous people have to guns. But our public officials seem more interested in political theater and special interest threats than in leadership. Congress, you must lead. Come together, take a sober look at the problem, and pass laws that protect our families and communities.”

They said they were prompted to draft the petition after last month’s Navy Yard shooting, and decided to release the letter after this week’s incident in which a 12-year-old Nevada boy fatally shot his math teacher, a Marine veteran of Afghanistan, and wounded two schoolmates before turning the gun on himself.

Asked about that incident at Tuesday’s White House press briefing, Press Secretary Jay Carney described President Barack Obama as “heartbroken” and declared that he “remains committed” to reviving his moribund legislative campaign.

Nothing visible has happened in Congress since March, three months after the mass slaying at Sandy Hook Elementary School in Connecticut, when the Senate voted to shelve legislation to expand background checks on would-be gun buyers, restrict sales of some semi-automatic weapons and limit ammunition magazines to 10 rounds.

“We made no secret of the fact that the president was very disappointed in the Senate’s failure to pass a bill,” Carney said. “He’s going to keep at it and keep looking at ways we can take these common-sense steps.”

Among the signers of the letter are eight retired Army and Marine generals, former Democratic Gov. Tony Knowles of Alaska and former GOP Rep. Joe Schwarz of Michigan.

None of the senators who were instrumental to writing the bipartisan measures rejected by the Senate — the background check plan got 54 votes, six fewer than needed — have suggested they are anywhere close to  growing those vote totals.

And Republican leaders in the House have been totally resistant to debating any sort of similar situation. Since the climactic Senate votes, meanwhile, the National Association for Gun Rights and the National Rifle Association and its subsidiaries have spent almost $4 million on lobbying to make sure their victories are not reversed