This time, it may be different.

That seems to be the hope after the Marjory Stoneman Douglas High School shooting in Parkland, Florida, that killed at least 17 people and injured at least 14 others. In the weeks after the shooting, students and activists have called on their peers around the country to demand action. This has so far culminated in two planned events: the National School Walkout on March 14 and the March for Our Lives on March 24.

The theme of both events: Enough is enough.

“Students and staff have the right to teach and learn in an environment free from the worry of being gunned down in their classrooms or on their way home from school,” Women’s March organizers, who are setting up the school walkout, said in a statement. “Parents have the right to send their kids to school in the mornings and see them home alive at the end of the day.”

Alex Wind, one of the survivors of the Florida shooting, echoed the sentiment on NBC’s Meet the Press: “We’re marching because it’s not just schools. It’s movie theaters, it’s concerts, it’s nightclubs. This kind of stuff can’t just happen. You know, we are marching for our lives, we’re marching for the 17 lives we lost. And we’re marching for our children’s lives and our children’s children and their children.”

The students behind the march have also formed a group, #NeverAgain.

Both the events will focus on calling Congress to act on gun violence. They follow several days of fiery speeches by students who survived the shooting, including one by Emma Gonzalez at a gun control rally on Saturday that went viral.

“Politicians who sit in their gilded House and Senate seats funded by the NRA telling us nothing could have ever been done to prevent this, we call BS,” Gonzales said. “They say that tougher gun laws do not decrease gun violence. We call BS. They say a good guy with a gun stops a bad guy with a gun. We call BS. They say guns are just tools like knives and are as dangerous as cars. We call BS. … They say that no laws could have been able to prevent the hundreds of senseless tragedies that have occurred. We call BS.”

It’s typical after mass shootings for there to be renewed calls for action around guns and gun violence — particularly with a push for Congress to enact gun control, which much of the research supports. It’s just as typical, however, for these calls to go nowhere: Despite the research and outrage, the demands eventually subside and the public and lawmakers by and large move on.

This has happened dozens of times over the years. The December 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut, in which a gunman killed 20 children, six adults, and himself, similarly led to calls for action. Since then, there have been more than 1,600 mass shootings. Many of these events led to speeches and events, but Congress refused to budge every time.

The hope is that this time could be different.

What the protests hope to accomplish

Here are the event details so far:

The National School Walkout , planned by Women’s March organizers, will be on March 14 at 10 am in each time zone. It calls for students, faculty, parents, and others to walk out of school for 17 minutes — one minute for each person who was killed in the Florida school shooting. For more, check out the official website and Facebook page.

, planned by Women’s March organizers, will be on March 14 at 10 am in each time zone. It calls for students, faculty, parents, and others to walk out of school for 17 minutes — one minute for each person who was killed in the Florida school shooting. For more, check out the official website and Facebook page. The March for Our Lives is scheduled for March 24. The details are thin right now, but students and activists plan to march on Washington, DC, and other US cities. For updates, check out the event’s official website.

The march in particular has drawn some big supporters, with Oprah Winfrey, George Clooney, and other celebrities donating hundreds of thousands of dollar to the event.

For both events, the idea is to show lawmakers that many people are fed up with the current state of gun violence in the US. Much of the focus is on mass shootings — with widely reported tragedies in Las Vegas; Sutherland Springs, Texas; Marshall County, Kentucky; and Parkland, Florida, in just the past five months alone.

While gun violence and homicides have generally declined over the past couple of decades, America is still a big outlier among developed nations when it comes to both. The US has nearly six times the gun homicide rate of Canada, more than seven times that of Sweden, and nearly 16 times that of Germany, according to United Nations data compiled by the Guardian. (Gun deaths are a big reason that America has a much higher overall homicide rate than other developed nations.)

Mass shootings actually make up a small fraction of America’s gun deaths, constituting less than 2 percent of such deaths in 2013. But these events are so horrific and affect so many people at once — in Las Vegas, the gunman killed 58 other people and wounded hundreds more — that they tend to get much more attention when they happen. And America sees a lot of these horrific events: According to CNN, “The US makes up less than 5% of the world’s population, but holds 31% of global mass shooters.”

This has been true for some time now, but after five months of particularly deadly mass shootings, it seems at least some activists are saying enough is enough.

Some of the response is also perhaps fueled by sentiment against President Donald Trump, who in his speech after the Florida shooting failed to mention gun control at all and tweeted over the weekend that Democrats are to blame for inaction on gun violence. (Although Trump has come around to some milder measures, which by and large improve enforcement of current law, over the past week.)

Just like they don’t want to solve the DACA problem, why didn’t the Democrats pass gun control legislation when they had both the House & Senate during the Obama Administration. Because they didn’t want to, and now they just talk! — Donald J. Trump (@realDonaldTrump) February 17, 2018

“You are in that exact position right now, and you want to look back on our history and blame the Democrats? That’s disgusting,” David Hogg, a survivor of the Florida school shooting, told NBC. “You’re the president. You’re supposed to bring this nation together, not divide us. How dare you? Children are dying, and their blood is on your hands because of that. Please take action. Stop going on vacation in Mar-a-Lago. Take action. Work with Congress.“

Gun control is popular, but it’s historically lacked sustained support

Congress’s inaction on guns over the past few years is not due to the unpopularity of gun control measures. If you look at the polling, support for gun control, depending on which specific measure respondents are asked about, can be very high among both Democrats and Republicans.

Here, for example, are the results of surveys by the Pew Research Center, which found strong support for measures ranging from an assault weapons ban to universal background checks to restrictions on people with mental illness buying guns.

Issue intensity seems to be the key reason nothing happens anyway. As Republican strategist Grover Norquist said in 2000, “The question is intensity versus preference. You can always get a certain percentage to say they are in favor of some gun controls. But are they going to vote on their ‘control’ position?” Probably not, he suggested, “but for that 4-5 percent who care about guns, they will vote on this.”

Other Pew surveys support Norquist’s claim. Consider this first chart:

About 21 percent of gun owners have contacted a public official to express an opinion on gun policy, compared to just 12 percent of non-gun owners. And about 22 percent of people who want less strict gun laws have contacted a public official, while just 15 percent of people who support stricter laws have.

The differences are more pronounced if you look at contact in the previous 12 months. Gun owners are 80 percent more likely than non-gun owners to have contacted a public official about gun policy in the past year. And supporters of laxer gun laws are nearly 60 percent more likely than supporters of stricter gun laws to have contacted a public official over the issue in the same time span.

This difference in issue intensity also shows up in other areas. Take this second chart:

Again, the situation is skewed in favor of gun owners. About 28 percent of gun owners have contributed to an organization that takes a position on gun policy, while only 10 percent of non-gun owners have. That helps explain how a group like the National Rifle Association (NRA) has become so powerful, while there are no political equivalents — in terms of influence — on the other side.

One caveat to the charts: Based on Pew’s surveys, there are way more adults in the US who believe that gun laws should be stricter (52 percent) than those who believe gun laws should be less strict (18 percent). So the side in favor of stricter gun laws can afford to have a lower percentage of its people contacting public officials.

It’s demonstrative, though, to focus on the 12-month data for this. As it shows, gun owners and supporters of laxer gun laws are more likely to have recently engaged a public official or political organization on this issue. That matters: If a senator gets phone calls every few months from gun owners and opponents of stricter laws, that’s going to make a bigger impression than calls from non-gun owners and supporters of stricter laws every year or so.

That’s especially true if you consider political party. Republicans are much more likely to oppose stricter laws, based on Pew’s data. So if a Republican senator mostly hears from GOP constituents, and these constituents are more likely to be really passionate about the issue since they are on the side that opposes stricter laws, that’s going to give the senator a skewed perception of where voters are on this topic. As a result, Republican lawmakers are more resistant to calls for gun control — arguing against “politicizing” mass shootings and focusing on issues like mental health instead.

So why the difference in passion? Kristin Goss, a political scientist at Duke University and author of The Gun Debate: What Everyone Needs to Know, previously told me that it’s a sense of tangible loss. Gun owners feel like the government is going to take their guns and rights.

This sentiment has been fueled by a decades-long public campaign by the NRA to convince the US public and politicians that, in fact, the Second Amendment guarantees an individual right to bear arms, and that more guns will actually make people safer (by letting them protect themselves), despite what the research says.

Gun control advocates, meanwhile, are motivated by more abstract notions of reducing gun violence — although, Goss noted, the victims of mass shootings and their families have begun putting a face on these policies by engaging more actively in advocacy work, which could make the gun control movement feel more relatable. That’s exactly what the current protests are doing, with student survivors from Florida in particular actively participating.

Will it work? That remains to be seen.

More guns, more gun deaths

Despite Congress’s dawdling, there is little question that America’s abundance of guns — the country has by far the highest rate of civilian gun ownership in the world — is driving its unique gun violence problem.

The research, compiled by the Harvard School of Public Health’s Injury Control Research Center, is pretty clear: After controlling for variables such as socioeconomic factors and other crime, places with more guns have more gun deaths.

“Within the United States, a wide array of empirical evidence indicates that more guns in a community leads to more homicide,” David Hemenway, the Injury Control Research Center’s director, wrote in Private Guns, Public Health.

This is true when you look at state-by-state data within the United States, as this chart from Mother Jones demonstrates:

And it’s true when you look at the data across developed nations, as this other chart from researcher Josh Tewksbury shows:

Experts widely believe this is the consequence of America’s relaxed laws and culture surrounding guns: Making more guns more accessible means more guns, and more guns mean more deaths. Researchers have found this to be true not just with homicides, but also with suicides, domestic violence, and even violence against police.

As a breakthrough analysis by UC Berkeley’s Franklin Zimring and Gordon Hawkins in the 1990s found, it’s not even that the US has more crime than other developed countries. This chart, from Jeffrey Swanson at Duke University, shows that the US is not an outlier when it comes to overall crime:

Instead, the US appears to have more lethal violence — and that’s driven in large part by the prevalence of guns.

”A series of specific comparisons of the death rates from property crime and assault in New York City and London show how enormous differences in death risk can be explained even while general patterns are similar,” Zimring and Hawkins wrote. “A preference for crimes of personal force and the willingness and ability to use guns in robbery make similar levels of property crime 54 times as deadly in New York City as in London.”

This is in many ways intuitive: People of every country get into arguments and fights with friends, family, and peers. But in the US, it’s much more likely that someone will get angry at an argument and be able to pull out a gun and kill someone.

Republican lawmakers tend to resist this research, instead focusing, particularly recently, on mental health as the key problem. But as Dylan Matthews explained for Vox, people with mental illnesses are more likely to be victims, not perpetrators, of violence. And Michael Stone, a psychiatrist at Columbia University who maintains a database of mass shooters, wrote in a 2015 analysis that only 52 out of the 235 killers in the database, or about 22 percent, had mental illnesses. “The mentally ill should not bear the burden of being regarded as the ‘chief’ perpetrators of mass murder,” he concluded. Other research has backed this up.

Guns are not the only contributor to violence. (Other factors include, for example, poverty, urbanization, and alcohol consumption.) But when researchers control for other confounding variables, they have found time and time again that America’s high levels of gun ownership are a major reason the US is so much worse in terms of gun violence than its developed peers.

To deal with its problem, America will have to not only make guns less accessible, but likely reduce the number of guns in the US as well.

The research also speaks to this point: A 2016 review of 130 studies in 10 countries, published in Epidemiologic Reviews, found that new legal restrictions on owning and purchasing guns tended to be followed by a drop in gun violence — a strong indicator that restricting access to guns can save lives.

The government can do something about this

Other wealthy countries have dealt with this problem, passing an array of gun control measures, from universal background checks to licensing requirements to outright bans and confiscation schemes.

In 1996, a 28-year-old man armed with a semiautomatic rifle went on a rampage in Port Arthur, Australia, killing 35 people and wounding 23 more. It was the worst mass shooting in Australia’s history.

Australian lawmakers responded with legislation that, among other provisions, banned certain types of firearms, such as automatic and semiautomatic rifles and shotguns. The Australian government confiscated 650,000 of these guns through a gun buyback program, in which it purchased firearms from gun owners. It established a registry of all guns owned in the country and required a permit for all new firearm purchases. (This is much further than bills typically proposed in the US, which almost never make a serious attempt to immediately reduce the number of guns in the country.)

The result: Australia’s firearm homicide rate dropped by about 42 percent in the seven years after the law passed, and its firearm suicide rate fell by 57 percent, according to a review of the evidence by Harvard researchers.

It’s difficult to know for sure how much of the drop in homicides and suicides was caused specifically by the gun buyback program. Australia’s gun deaths, for one, were already declining before the law passed. But researchers David Hemenway and Mary Vriniotis argue that the gun buyback program very likely played a role: “First, the drop in firearm deaths was largest among the type of firearms most affected by the buyback. Second, firearm deaths in states with higher buyback rates per capita fell proportionately more than in states with lower buyback rates.”

One study of the program, by Australian researchers, found that buying back 3,500 guns per 100,000 people correlated with up to a 50 percent drop in firearm homicides and a 74 percent drop in gun suicides. As Matthews noted, the drop in homicides wasn’t statistically significant because Australia already had a pretty low number of murders. But the drop in suicides most definitely was — and the results are striking.

One other fact, noted by Hemenway and Vriniotis in 2011: “While 13 gun massacres (the killing of 4 or more people at one time) occurred in Australia in the 18 years before the [Australia gun control law], resulting in more than one hundred deaths, in the 14 following years (and up to the present), there were no gun massacres.”

This is the kind of action the US — and specifically Congress and President Trump — could take. But they have long gotten a pass on this issue. Will this time be different?