WASHINGTON — It did not take long after the racist gun massacre in Buffalo for a familiar sense of resignation to set in on Capitol Hill about the chance that Congress would be able to muster the will to act on meaningful legislation to combat gun violence in America.

In emotional remarks at the scene of the mass shooting on Tuesday, President Biden made no call for such action, and afterward, he was frank about his belief that persuading Congress to move would be “very difficult.”

Around the same time, top Democrats on Capitol Hill were publicly conceding that their paper-thin majority in the Senate meant there was little they would be able to do to prevent the next tragedy.

“We’re kind of stuck where we are, for the time being,” said Senator Richard J. Durbin, Democrat of Illinois and the chairman of the Judiciary Committee, playing down the chance that even a modest bill to strengthen background checks for gun purchases could overcome a Republican blockade.

Senator Christopher S. Murphy, Democrat of Connecticut, shares his colleagues’ skepticism that any legislation can move. But he is also concerned that Democrats may squander a chance to turn the issue of gun safety into a rallying cry for the midterm elections.

For a decade, the issue of gun violence has defined Mr. Murphy’s career; the 2012 massacre at Sandy Hook Elementary School in Newtown, Conn., took place a month after he won his seat.

Mr. Murphy spoke to The New York Times from a Senate cloakroom about the chances for legislative action on guns, what Mr. Biden should do and why he thinks Democrats will lose control of Congress if they don’t make combating gun violence the core of their 2022 appeal to voters.

The interview has been lightly edited and condensed for clarity.

After the Sandy Hook Elementary School shooting, when 20 young children and six adults were killed, did Democrats and President Barack Obama miss the opportunity to pass meaningful gun safety legislation?

There was this popular meme in 2013, which said that if the killing of 20 children didn’t result in any action, nothing will. That’s fundamentally the wrong way to look at how Washington works. There are few epiphanies here. It’s all about political power, and political muscle, and we’re in the process of building our own.

The National Rifle Association and the gun lobby was ready for us, and for those parents, in 2013. The anti-gun-violence movement was essentially nonexistent, and the N.R.A. was at its peak power.

We needed time to build up a movement that is stronger than the gun lobby.

My worry is that a lot of my colleagues still believe in the mythology of 1994, when everyone thought Democrats lost Congress over the assault weapons ban. That’s not true — that’s not why Congress flipped. Ever since then, Democrats are under the illusion that it’s a losing issue for us.

It’s one of the most important wedge issues, and if we don’t talk about it, then we’re going to lose.

Many are urging Senator Chuck Schumer and Mr. Durbin to bring up a bill to expand background checks. Even if it couldn’t pass, it would force Republicans to defend their opposition to a policy that polls show has broad support. Should they?

There are times when show votes help define the parties. I’m not confident this is one of those moments, given the fact that it’s already pretty clear which side Republicans fall on and which side Democrats fall on.

My main recommendation is for Democrats to go out and run on this issue, proudly and strongly. My worry is we would have a vote on the Senate floor, but then Democrats would not be willing to go out and talk about that vote in campaigns.

The only way we actually change the dynamic on this issue is to make Republicans show we believe this is a winning electoral issue. That’s what we did in 2018. My worry is, we don’t feel the same confidence in this issue as a winning electoral issue in 2022.

I don’t know why we don’t learn a lesson from 2018, that when we run strongly on the issue of guns, universal background checks, banning assault weapons, we turn out voters that otherwise would stay home in the midterms. I’ve talked to Senator Schumer about bringing a vote to the Senate floor. I’m not interested in taking a vote on the Senate floor if we don’t talk about it.

If legislation can’t pass, what executive actions are you pushing the administration to take?

There is still a ton of harmful gray area around the question of who needs to be a licensed gun dealer. There are a lot of folks peddling guns online and at gun shows who are truly in the business of selling guns, and should be required to do background checks. President Obama put out helpful, but not binding, guidance. The administration could put some real meat on the existing statute and define what it means to be in the business of selling guns.

Have you pitched that to them?

I have. There has been significant interest from the White House in pursuing that line of policy. I don’t know that they have made a commitment or issued any directive to the Justice Department.

Do you support eliminating the filibuster in order to pass gun reforms?

One hundred percent. The reason we can’t get this done is the rules of the Senate, not because the American people haven’t made a choice.

Guns were one of the most important issues for voters in 2018; it ranked second behind health care. When voters came to the polls in 2018 and elected a Democratic majority in the House, it was with the explicit purpose of getting gun legislation passed. The same voters came back and elected a Democratic president. It’s simply the rules of the Senate that stopped the will of the American people from becoming law.

Is there anything happening in terms of discussions with Senators Joe Manchin III, Democrat of West Virginia, and Patrick J. Toomey, Republican of Pennsylvania, about trying to revive their bill to tighten background checks?

There’s nothing new happening now. Manchin-Toomey doesn’t have 60 votes. I spent much of the last two years trying to find a piece of Manchin-Toomey that could get 60 votes. Ultimately, we couldn’t find a landing place. I’ll continue to try any creative avenue to find an expansion of background checks.

Does a weakened National Rifle Association create any opening for Republicans to move off their opposition to gun safety measures?

This N.R.A. stamp of approval still really matters to them. Inside a Republican Party that has become bereft of big ideas, they’ve only got one left, which is the destruction of government. Nothing signals that more than the endorsement of the organization that supports people arming themselves against the government. In this era of anti-government fervor, it’s more important than ever.

Eventually, we have to figure out a way for Republicans to show how much they hate government other than the N.R.A. endorsement. Maybe I should be rooting for the Club for Growth to be a more effective voice within the Republican Party.

Can guns really be a winning issue for Democrats in a year when Republicans are attacking your party over inflation, rising gas prices and not meeting the basic needs of American families?

I think voters are emotionally moved by the slaughter of innocents. And I think they find it a little weird when Democrats who claim to care about this don’t actually talk about it.

We live in an era where authenticity is the coin of the realm. You just have to show voters who you are. I don’t think there’s any more potent means by which to translate who you are, and what you care about, than this issue. I think when you leave this out when you list your priorities as a candidate, it causes voters to scratch their heads a bit.

What grade would you give the Biden administration on this issue?

The administration could have moved faster on executive actions and the appointment of a new A.T.F. director. I want them to keep going. There’s still more regulatory and executive action that this administration can take and more things the team can do to use the bully pulpit to make sure this is an election issue.

Would you give the administration a grade?

No.

A number of gun violence prevention organizations have called on Mr. Biden to open a White House Office of Gun Violence Prevention. Do you think that would make a difference?

I do. It’s become clear to me we need a specific, driving focus on gun violence. The president is clearly personally committed to this issue, but he’s stretched thin due to myriad international and domestic crises. He would be best served by a high-level senior official who wakes up every day and coordinates the issue.

After another mass shooting like the one in Buffalo, do you find yourself becoming resigned to the idea that nothing can be done on gun violence?

I’ve studied enough great social change movements to know they often take decades to succeed. It was a full 10 years from the shooting of James Brady to the passage of the Brady handgun bill. I think I am part of one of these great social change movements, and I’m confident that you have to put up with a lot of failures before you’re met with success.

I also don’t think democracy can allow for 80 percent of the American people to not get their way, forever. Eventually we will be able to break through. We just have not been able to find that pathway yet.

This is an exhausting issue to work on, but I have this very deep sense that I will see my time in public service as a failure if I don’t meet the expectations of those parents in Sandy Hook, and Hartford and Bridgeport. And fear is a powerful motivator.