During an event in Nevada, Democratic presidential candidate Hillary Clinton addressed the church shooting in Charleston, S.C., and gun control. (United States Conference of Mayors)

In her standard stump speech, Hillary Rodham Clinton talks about fighting income inequality, celebrating court rulings on gay marriage and health care, and, since the Emanuel AME Church massacre, toughening the nation’s gun laws.

That last component marks an important evolution in presidential politics. For at least the past several decades, Democrats seeking national office have often been timid on the issue of guns for fear of alienating firearms owners. In 2008, after Barack Obama took heat for his gaffe about people who “cling to guns or religion,” he rarely mentioned guns again — neither that year nor in his 2012 reelection campaign.

But in a sign that the political environment on guns has shifted in the wake of recent mass shootings — and of Clinton’s determination to stake out liberal ground in her primary race against insurgent Sen. Bernie Sanders (I-Vt.) — Clinton is not only initiating a debate about gun control but also vowing to fight the National Rifle Association.

“I’m going to speak out against the uncontrollable use of guns in our country because I believe we can do better,” Clinton said Tuesday in Iowa City.

A few days earlier, she said in Hanover, N.H.: “We have to take on the gun lobby. . . . This is a controversial issue. I am well aware of that. But I think it is the height of irresponsibility not to talk about it.”

Sen. Bernie Sanders (I-Vt.) is drawing big crowds, such as Monday’s rally in Portland, Maine, but gun control is an issue on which Hillary Rodham Clinton has a more progressive record. (Robert F. Bukaty/AP)

Clinton’s comments could stoke millions of politically active gun owners, and Wayne LaPierre, the NRA’s executive vice president, argued that the move was fraught with peril for her.

“We’ve been down this road before with the Clintons,” ­La­Pierre said through a spokesman. “She needs to read her husband’s book.”

In his memoir, “My Life,” former president Bill Clinton suggested that his vice president, Al Gore, lost the 2000 presidential election in part because of backlash in states such as Arkansas and Tennessee over the Clinton administration’s 1995 ban on assault weapons, which has since expired. Many Democratic lawmakers also lost their elections after gun-control votes.

The Republican 2016 presidential candidates, in keeping with GOP orthodoxy, have spoken out loudly against gun control. Many gave speeches at the NRA’s spring convention and tout their high ratings from the group.

Mark Glaze, a longtime gun-control advocate who until recently oversaw former New York mayor Michael R. Bloomberg’s gun-control efforts, argued that Hillary Clinton should embrace her husband’s record.

“The Clintons pulled off the almost-impossible by giving us the background-check system and banning assault weapons,” Glaze said. “That’s something President Obama wasn’t able to do. Their political interest lies in owning, rather than obscuring, that accomplishment.”

Many Democratic strategists said campaigning on guns is smart politics for Hillary Clinton both in the primary and, should she become the nominee, in the general election.

Gun control is one of the few issues on which Clinton has a more left-leaning record than Sanders, who represents a rural, pro-gun-rights state and has voted in the past for legislation to protect the firearms industry. Although Clinton has not attacked Sanders by name, by invoking guns she makes an unspoken contrast.

The issue also fits neatly into the overall narrative Clinton is trying to present. She can stake out a bold stance on an issue that plays well with the liberal base while arguing that she would break through the partisan stalemate in Washington.

There are few issues more in­trac­table than guns. In 2013, after the massacre of 20 young children and six educators at an elementary school in ­Newtown, Conn., a bipartisan compromise to expand background checks for firearm purchases failed to pass the Senate despite overwhelming popular support and President Obama’s backing.

Clinton began talking about gun control in the days following last month’s church shooting in Charleston, S.C., and aides said she plans to keep it in her stump speech, although she has no immediate plans to unveil a detailed gun policy.

“This is an important issue, and she believes that we cannot let partisan gridlock prevent us from continuing to seek ­common-sense safety measures,” said Clinton campaign spokesman Brian Fallon.

Despite his mixed voting record, Sanders did support the 2013 background-check bill and ­assault-weapons ban. And on the stump, he is trying to sound more forceful. He notes that “guns in Chicago and Los Angeles mean a very different thing than guns in Vermont and New Hampshire” but says — as he did two weeks ago in Bow, N.H. — that the next president must “come forward with a common-sense proposal on guns.”

In the Democratic field, former Maryland governor Martin O’Mal­ley has the strongest record in favor of gun control. He supported an assault-weapons ban as mayor of Baltimore in the early 2000s and then signed one into law as governor in 2013, along with a suite of gun restrictions that stand as among the nation’s toughest.

“He’s the only person in the race who’s led on this issue,” said O’Malley spokeswoman Haley Morris.

Looking to the general election, some gun-control measures are popular, especially with the coalition of swing-state Latinos, African Americans, and young and suburban women the Democratic nominee would need to win the White House.

“There is no more powerful force in an election than the suburban mother, and you don’t find a lot of suburban mothers that are against some sort of common-sense gun control,” said Mo ­Elleithee, a former Clinton adviser and Democratic strategist who now directs the Georgetown Institute of Politics and Public Service.

Other Democrats argue that Clinton has nothing to lose. Sen. Timothy M. Kaine (D-Va.) said the NRA has become a “paper tiger,” noting the elections he’s won despite the NRA’s vocal opposition.

“I think she has no illusion that even if she didn’t say a word about guns, the NRA would be out there blasting her to say she had a conspiratorial plan to work with the U.N. to take everybody’s guns away, so why not go head-on on an issue that will improve safety,” Kaine said.

A survey this year by the Johns Hopkins Center for Gun Policy and Research found that 89 percent favor requiring background checks for all gun sales, including 85 percent of gun owners. But polling is much more closely divided on other gun restrictions and does not account for the high intensity among gun-control opponents.

David “Mudcat” Saunders, a Democratic strategist based in conservative rural Virginia, warned that Clinton’s focus on guns could taint the entire Democratic ticket, including candidates for state and local offices.

“Never in the history of the Democratic Party have they started a gun debate that didn’t cost them numbers in the general election,” said Saunders, who supports the candidacy of former senator Jim Webb (D-Va.). “She’s trying to get to the left of Bernie, obviously, but I think it’ll hurt her in the long run — and it’ll cost anybody on the down ticket in the South and in rural America.”

In her 2008 presidential campaign, Clinton stayed nearly silent on guns. An exception was after Obama’s “cling to guns” comment surfaced, when she attacked him as being “elitist” and fondly recalled her father teaching her to shoot as a little girl at her grandfather’s Pennsylvania lake house.

Howard Wolfson, for many years a top Clinton aide before going to work for Bloomberg, said Clinton’s avoidance of guns in 2008 should not be mistaken for a lack of interest in gun control.

“I started working for her back in 1999 and she talked about it back then,” Wolfson said. “As a senator from New York, it was something that was important to her. I think in the wake of Newtown and Charleston, it’s more resonant in our political culture.”

In recent months, Clinton’s speechwriters and policy staff have sought counsel from Bloomberg’s group, Everytown for Gun Safety. Erika Soto Lamb, ­Everytown’s spokeswoman, said Clinton’s focus on the issue is “striking.”

“Knowing how hard we tried in 2012 to get [Republican nominee Mitt] Romney or Obama to say something about guns,” she said, “it is a changed world now when Hillary and other candidates are making it a part of their stump. This is the first presidential election when we’ve seen proactive statements.”

Jose DelReal in Iowa City and Scott Clement in Washington contributed to this report.