The retired Marine general, flanked by former military colleagues, thunders a warning: Elect our candidate, a tough, smart, proven leader, or risk turning the nation over to a novice who would retreat from the world stage and who disrespects the military. “USA! USA!” the rapturous crowd chants in response.

This set-piece of Republican conventions returned in full swing this summer. Except this time, it was happening in Philadelphia, at the Democratic Convention.

Recently, something significant has changed in the way that Democrats approach national security—something that cannot be explained simply as a response to Donald Trump’s manifest unfitness to be commander in chief. Rather, the party that has long yielded to its political rivals on the question of who best can secure the country is standing up and exerting its own primacy on these issues. Now, with security experts from both parties lining up behind their nominee, Democrats could be in a position to reverse the long-standing politics of national security for the first time in decades.

After the political wipeout in 2004, Third Way conducted extensive public opinion research to explore what we, at Third Way, dubbed “the security gap.” Since the Vietnam War, when liberals were seen as soft on defense, Republicans have led by 10-25 points in polls that asked respondents which party is better able to protect the country. This gap persisted despite strong national security leadership in the Democrats’ two-term presidents, Bill Clinton and Barack Obama. And the rare exceptions have proved the rule: Democrats closed the gap, or briefly led on this issue, only twice since 9/11—at the nadir of the Iraq War in 2006, and after Obama’s bold stroke took out Osama bin Laden in 2011. But, in both cases, Republicans quickly regained their edge on security politics.

This raises serious concerns, and not just for the electoral prospects of Democrats. If voters believe that one party—the party that has controlled the White House for 16 of the last 24 years—is not tough enough to defend the country, that helps to further erode trust in government—and in dangerous ways.

Focus groups over the last decade highlighted a clear and consistent problem: Voters thought of Democrats as weak, vacillating, and afraid to use force in order to protect the country. While they liked the party for their foreign policy and alliance-building, they strongly preferred Republicans when it came to battling our enemies. And when they do give Democrats credit for those things, it’s short-lived.

Our 2014 focus groups brought this problem home. In a group of swing-voting women, when asked to identify something positive about Democrats on security, they sat in uncomfortable silence until one haltingly referenced the attack “on that one guy with the beard.” Just three years after the Abbottabad raid, bin Laden’s name had faded from memory.

That year, despite our warnings that the “gap” was back, and bigger than ever, Democrats turned a blind eye to security. One prominent Democratic pollster said, “We should not conflate an expression of concern about terrorism with it as a driver of vote choice.” And Democrats continued to minimize the very threats that, as our focus groups showed, voters were particularly concerned with. In a campaign debate, then-Senator Mark Udall, a Democrat, claimed, “ISIS is not an imminent threat.” Udall and eight other Senate Democrats lost their seats that year—security was the sleeper issue. Republicans ran ads that combined all of the public’s most pressing anxieties. One ad in North Carolina actually claimed that ISIS was bringing Ebola across the Mexican border.

Democrats started getting the message. By the spring of last year, POLITICO and USA Today were claiming that national security was creating real problems for Democrats, leading both Democrats in Congress, as well as the Clinton campaign, to pay close attention. Consequently, Third Way was involved in briefing the Democratic caucus on this issue, and was frequently asked for advice when terrorism hit the front page. Even Russ Feingold, the sole vote against the PATRIOT Act, began running tough on terrorism in his quest to return to the Senate.

It was clear that most in the party finally understood three things: First, in the wake of terrorist attacks at home and abroad, national security carries a high degree of salience for voters. Second, Republicans will use the same playbook that they always have to exploit their perceived advantage on security. Third, with a tough, tested, experienced person like Hillary Clinton as the Democratic nominee—and particularly with Donald Trump as her opponent—a window has opened to reclaim the advantage on security politics.

After the take-no-prisoners convention, a POLITICO headline declared, “Role Reversal: The Dems Become the Security Party.”

Of course, this isn’t a complete surprise. This year’s Democratic nominee has deep national security experience and internationalist instincts. But so did John Kerry, a decorated war hero. And so did Al Gore, a Vietnam vet and two-term vice president. Their conventions, and their campaigns, did not, to put it mildly, overly emphasize muscular internationalism.

Republicans are not simply going to cede the political territory they have commanded for a generation. Trump’s convention featured an incessant, and relatively effective, focus on supposed global danger. But this time, Democrats haven’t tried to deflect the criticism or veer toward more familiar ground. They have, at long last, begun to, forcefully, make the case that they are, in fact, the true party of national security.