Again with the gun debate. And the national outrage. And the sad, frustrating push for legislative change with an improbable chance of passing.

If the killing spree that took the lives of 20 children and six adults at Sandy Hook Elementary School in Connecticut five years ago didn't spur gun reforms, and if the slaying last year of 49 people at Pulse Nightclub in Orlando didn't either, policy analysts say it's difficult to imagine legislative action on firearms materializing in response to Sunday's massacre in Las Vegas.

Not even given its grim new standing as the deadliest mass shooting in modern U.S. history.

In the aftermath of the attack in Vegas, which left at least 58 dead and more than 500 injured, Democratic House minority leader Nancy Pelosi is calling for the formation of a bipartisan select committee for "common sense" gun laws. 

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A woman lights candles at a vigil on the Las Vegas Strip following on Oct. 2. (Chris Wattie/Reuters)

U.S. President Donald Trump acknowledged the growing anger of legislative inaction, telling reporters on Tuesday, "We will be talking about gun laws as time goes by."

But former president Barack Obama was unable to pass gun measures in the face of a Republican Congress after what happened in Sandy Hook and in Orlando. Following that pattern, it's likely nothing will change legislatively in the wake of the Las Vegas attack, either, says Steve Billet, director of the master's of legislative affairs program at George Washington University's School of Political Management.

Pundits agree that achieving stricter gun control is even more politically infeasible now, with a new Republican president whose party controls both chambers of Congress. 

NRA a Trump backer

Trump, whose ascension to the Oval Office was fuelled by the National Rifle Association's endorsements, has no political incentive to risk angering the powerful gun lobby group.

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Democratic House minority leader Nancy Pelosi sent a letter to House Speaker Paul Ryan requesting the creation of a committee to examine U.S. gun laws after the Las Vegas massacre. (Joshua Robert/Reuters)

Strong congressional NRA ratings are coveted among conservatives. And Democrats and gun-control advocates "just don't have the sort of political organization that the NRA has," Billet said.

He said the NRA has effectively bent the will of legislators who feel beholden to the organization, owing to its sway among rural voters. The gun lobby frequently makes recommendations for who members should vote for, and which campaigns to donate to.

"Let's face it," he said. "The Republicans are in control in Washington and it's their relationship with the NRA that's basically defining the political environment."

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U.S. President Donald Trump stands with his wife, Melania, Vice-President Mike Pence and his wife, Karen, during a moment of silence in the wake of the mass shooting in Las Vegas, at the White House on Oct. 2. (Kevin Lamarque/Reuters)

Billet said members of Congress know full well they risk being "punished" by the NRA, risking harm to their records of protecting the Second Amendment, and encouraging potential primary challenges.

No path forward

Nelson Lund, a law professor at George Mason University who defends the individual right to bear arms, argues that demands to restrict gun access after Las Vegas are complicated by what seems to be inability so far for legislators to identify how any new laws — short of taking away all firearms and dismantling the Second Amendment — would have prevented Sunday's massacre.

When it comes to legislative reforms, "don't hold your breath at the national level," Lund said, noting that the 64-year-old gunman in Vegas, who later took his own life, managed to pass background checks and purchased his dozens of firearms legally. The shooter had no criminal record or known history of mental illness.

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Democratic legislators speak on Capitol Hill in Washington, D.C., in June 2016 after House Democrats ended their sit-in protest on the House floor over inaction on gun control. (Carolyn Kaster/Associated Press)

Lund also noted that even while Obama and the Democrats had control over Congress in 2009, "they didn't do anything" on gun control with solid majorities in both houses. Rank-and-file Democrats at the time sided with gun-rights advocates on a vote to lift prohibitions on people bringing guns into national parks. 

The U.S. has since become more polarized.

Democratic legislators are now renewing a push for expanded background checks, a ban on assault-style weapons and limits on high-capacity magazines. Sen. Dianne Feinstein of California has pushed for the curbing of so-called "full auto" kits, which allow owners to convert semi-automatic firearms into weapons capable of firing a string of bullets with a single squeeze of a trigger.

(After the Las Vegas gunman took his own life, weapons seized from his hotel room included semi-automatic weapons altered to be used as a fully automatic rifle.)

Handguns a greater threat

While the Vegas massacre revived calls for the federal Assault Weapons Ban that expired in 2004, Robert Cottrol, an expert on Second Amendment laws with George Washington University, wonders if that's "bringing attention to the wrong issue."

Of the 11,008 Americans killed in gun-related homicides in 2012, according to FBI data, only 322 involved a rifle of any kind.

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Clark County Sheriff Joe Lombardo, centre, responds to a question during a media briefing in Las Vegas on Tuesday. (Steve Marcus/Las Vegas Sun/Associated Press)

In terms of gun-related homicides, Cottrol said, the odds of being killed by an assault rifle are "like getting hit with lightning." 

Statistically, shaping gun control policy around assault weapons may not make sense. 

"The real criminological issue in the United States is not the assault rifle. What we ignore is the day-to-day carnage, particularly in inner-city communities, with handguns," he said. 

'Moral thing to do'

To Lori Haas, too many Americans are experiencing the tragedy as personally as she did 10 years ago.

Her daughter, Emily, was wounded in the 2007 Virginia Tech shooting when a 23-year-old senior opened fire on her French class and elsewhere around the campus, killing 32 people. A decade ago, it was the single deadliest such massacre ever by a civilian gunman. It remained so until last year, when the Pulse club shooting occurred.

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Las Vegas police officers patrol Tropicana Avenue near Las Vegas Boulevard after the mass shooting. (Ethan Miller/Getty Images)

"And here we are, 15, 16 months later, and now we have a shooting in Las Vegas that now qualifies as the largest mass shooting," Haas said from Richmond, Va. "It's horrific and absurd, in a way."

It's unclear how Democrats, some of whom have boycotted moments of silence and staged sit-ins to protest the inaction on gun laws, can shift their strategy to effect the legal reforms they want.

Gun show Loophole

A December 2007, file photo shows Lori Haas, left, with her daughter Emily, a Virginia Tech shooting victim. Haas, who is now a gun-control activist, says she'll continue pushing for stricter firearms laws despite inaction from Congress. (Steve Helber/Associated Press)

Haas is frustrated by congressional gridlock holding up passage of what she believes to be important gun reforms. Now the Virginia state director at the Coalition to Stop Gun Violence, she said she'll nevertheless push for stricter measures, such as a ban on people subject to domestic violence protective orders from obtaining guns.

"To me, it's a moral obligation to do something about the epidemic of gun violence," she said. "Just because it's something some think is futile doesn't mean you don't do it. Especially if it's the moral thing to do."