Sen. Dianne Feinstein (D-Calif.) unveiled a bill that would ban “bump stocks,” devices that can be purchased online to make legal semiautomatic weapons fire more like automatic guns, on Oct. 4. (Reuters)

It didn’t work after mass shootings at a nightclub in Orlando, college campuses in Virginia and Oregon, a church in Charleston, or at a movie theater and high school in Colorado. Or after two lawmakers survived assassination attempts. But after a gunman killed 58 people and wounded more than 500 at a Las Vegas concert, Democrats are going to try again to revamp the nation’s gun laws.

And some Republicans signaled that this time may be different.

Stunned by the carnage caused at a country music festival by one heavily armed gunman and embittered after years of fruitless attempts at gun control, congressional Democrats on Wednesday unveiled new narrowly tailored proposals to ban devices used in the shooting and revived old ideas to close loopholes and restrict some gun purchases.

The fresh push comes at a fractured moment in American politics, but Democrats believe that the scope of the carnage might make a difference. Some senior Republicans dismissed talk of new gun legislation as insensitive or premature, but ardent Second Amendment supporters said they are at least open to discussing new laws — and one senator said he supports banning certain accessories used in the shooting.

Even President Trump might be open to a debate. While he campaigned as a fierce defender of gun rights, this week he said, “We will be talking about gun laws as time goes by.”

As America grapples with the increasing frequency and deadliness of mass shootings, politicians are turning to scripted reactions to respond to the tragedies. (Jenny Starrs/The Washington Post)

As Trump flew aboard Air Force One to Las Vegas to meet with survivors of the shooting, Sen. ­Dianne Feinstein (D-Calif.) unveiled a bill that would ban “bump stocks,” devices that can be purchased online for $200 to make semiautomatic weapons fire more like automatic weapons.

At least a dozen of the 23 firearms recovered in Las Vegas were semiautomatic rifles legally modified using bump stocks.

After 20 children and six adults were killed in the December 2012 Sandy Hook Elementary School shooting in Connecticut, Feinstein introduced a bill to reinstate a federal assault weapons ban. The measure failed by a wide margin. What Feinstein unveiled Wednesday is drawn from part of her 2013 bill but focuses only on bump stocks and similar accessories. Hunting accessories would still be permitted.

“The thing is really well worded, because it’s short, it’s plain-spoken language,” Feinstein explained. “So, everybody will know exactly what’s banned, no matter how fancy or how simple the device is.”

She called on regular Americans: “Mr. and Mrs. America, help us. We know the power on the other side. You have to help us.”

Feinstein’s announcement played out like a scene she has staged several times before. Just as most Republicans take cues on national security from Sen. John McCain (R-Ariz.), Democrats for decades have turned to Feinstein, whose political career is inextricably tied to gun violence.

Feinstein became San Francisco mayor in 1978 after the assassinations of Mayor George Moscone and Supervisor Harvey Milk. On Wednesday, she said that her own personal history with gun violence could have become even worse — her grown daughter had planned to attend the country music festival in Las Vegas with friends but ultimately did not.

“I know what guns can do,” Feinstein told reporters. What transpired in Las Vegas, she said, “is taking it into war.”

Feinstein said she had yet to identify potential Republican co-sponsors, but Sen. Ron Johnson (R-Wis.) said he would support banning bump stocks: “I have no problem banning those,” he told reporters.

Sen. John Cornyn (Tex.), the ­second-ranking Senate Republican, said that hearings on banning bump stocks would make sense. Sen. John Thune (R-S.D.) said that a potential ban “is worth having a conversation about, and some of our members agree with that.”

Other senior Republicans indicated that the latest tragedy is not going to change their position.

In an interview Wednesday, House Majority Whip Steve Scalise (R-La.) — who returned to Congress last week after surviving a shooting in July — agreed. “I think it’s a shame that the day somebody hears about a shooting, the first thing they think about is, how can I go promote my gun-control agenda, as opposed to saying, how do I go pray and help the families that are suffering?”

On Tuesday, Senate Majority Leader Mitch McConnell (R-Ky.) told reporters that it’s “completely inappropriate to politicize an event like this.” He declined to answer questions on the subject.

Sen. Lindsey O. Graham (R-S.C.) said Wednesday that the ban is “something I’d be interested in looking at to see if a law change would matter. Would it affect things? I’d be willing to look at that.”

Even some House Republicans who are among the most avid supporters of gun rights said they had not heard of bump stocks before this week.

“This is such a new component to me, I have no idea how it operates, how simple it is,” said Rep. Jeff Duncan (R-S.C.), who has sponsored numerous bills to expand gun rights, including a stalled effort to partially deregulate silencers. Conversations are underway among conservatives about how to approach the issue.

Others, such as Sen. Richard C. Shelby (R-Ala.), were unmoved: “I’m a Second Amendment man,” he told reporters. “I’m not for any gun control.”

Beyond Feinstein, Sen. Richard Blumenthal (D-Conn.), a fierce gun-control advocate since the Sandy Hook massacre, said he would reintroduce a plan to close a loophole allowing gun dealers to sell weapons after three days if the FBI has not yet completed a background check on the buyer.

Sen. Chris Murphy (D-Conn.) also intends to reintroduce a bill to change the national background check system. Sen. Edward J. Markey (D-Mass.) plans to reintroduce legislation that would allow qualified gun owners to use “smart gun” technology that can restrict who can use a weapon.

The National Rifle Association, the nation’s most prominent gun rights organization, did not have immediate comment and has remained publicly silent since Sunday’s mass shooting in Las Vegas.

Complicating the fresh debate for Democrats is their own electoral map next year. Ten Democratic senators face reelection bids in mostly rural states that Trump easily won.

A spokeswoman for Sen. Joe Donnelly (D-Ind.) did not immediately respond to requests for comment.

Sen. Heidi Heitkamp (D-N.D.) said in a statement that she did not know much about bump stocks, “and I first want to learn more about them.”

Sen. Joe Manchin III (D-W.Va.) said that Feinstein’s idea “sounds sensible and reasonable to me” but that he would consult hunters in his state before taking a position. Spokesmen for Sen. Bill Nelson (D-Fla.), who faces an uphill fight next year in his swing state, and Sen. Claire McCaskill (D-Mo.), who is running for reelection in a state that Trump won by 18.5 points, said they would co-sponsor Feinstein’s bill.

“The notion that we’re allowing an add-on that allows people to convert a semiautomatic weapon to an automatic weapon — we’ve got to address that,” McCaskill said.

Democrats believe Trump might also support new laws, citing his past support for gun-
control measures after the Sandy Hook shooting. When President Barack Obama called on Congress to enact new measures, Trump — then a private citizen — tweeted his support.

Senate Minority Leader Charles E. Schumer (D-N.Y.) said Trump has a “responsibility” to take up the issue.

“In the past, he’s been very reasonable about the gun issue,” Schumer said.

But Richard Feldman, a former NRA lobbyist who now leads the Independent Firearm Owners Association, said the latest debate is likely to focus too much attention on the tools used instead of why people lash out so violently.

“What sucks (to me anyway) is how we allow these bizarre events to focus our attention on the kind of gun, or caliber of gun instead of the person misusing the gun,” Feldman said in an email.

“The only people who care about guns 30 to 60 days after a tragedy are gun owners,” he added, “and gun owners won’t allow the actions of a murderer to dictate the rights of the rest of us.”

Mike DeBonis, Sean Sullivan and David Weigel contributed to this report.