President-elect Joe Biden campaigned on one of the most extensive gun reform agendas in American history. He pledged to ban the manufacture and sale of assault weapons and high-capacity magazines, institute a voluntary gun buy-back program, and direct more than $900 million in funding to community-based violence intervention programs.

Biden won’t be able to do all that on his own. He’ll need the support of the House, which remains under Democratic control, and the Senate, where the majority is in question. Early January’s runoff elections in Georgia will determine the balance of power in the Senate — or if there will be a 50-50 split in the chamber, with Vice President-elect Kamala Harris casting the tie-breaking vote.

Under a Republican Senate majority, many of Biden’s gun reform proposals are likely to be dead on arrival. And even a best-case scenario for Democrats does not ensure they will advance. If Democrats manage to gain control of the Senate, the filibuster rule and centrist Democratic Senator Joe Manchin may present roadblocks.

In either scenario, the Biden administration isn’t without options. Although the president doesn’t have the power to change existing laws or enact new ones on his own, he has the authority to direct agencies, set priorities, appoint leadership, and more. And Biden’s campaign signaled his willingness to act even if his proposals stall in the Senate. “Joe Biden also knows how to make progress on reducing gun violence using executive action,” his website reads.

What Biden does is sure to be shaped by his experience leading gun reform efforts over the course of his career. After the mass shooting at Sandy Hook Elementary School in 2012, President Barack Obama tapped him to draw up sweeping gun legislation. When bills to expand background checks and ban assault weapons failed in the Senate without Republican support, Obama signed more than two dozen executive orders to improve enforcement of existing laws and strengthen background check databases. But the effort largely failed to curb access to firearms.

Another push following the 2015 San Bernardino shooting required the Social Security Administration to turn over to the federal background check system records of people who were adjudicated as mentally ill, and was intended to get the Bureau of Alcohol Tobacco, Firearms and Explosives to more aggressively enforce the law requiring people “engaged in the business” of selling guns to conduct background checks. After Obama signed the directive, aimed at closing the so-called private sale or gun show loophole, the ATF said it was undertaking no new enforcement efforts, and gun show organizers compared it to “fairy tales,” saying it had no effect on their business.

Many of Obama’s executive actions were simply “guidance,” not binding regulation, framed as clarifying and enforcing existing law, not substantially expanding federal oversight of the gun industry. Gun violence prevention groups are keen on getting the Biden administration to act more decisively. On November 17, a coalition of 86 national, state and local violence prevention groups signed a letter to Biden’s transition team laying out a list of recommended executive actions the administration could take. While Obama’s executive actions had a negligible effect, and were narrow by design, gun reform advocates say the efforts provide lessons for the next president.

“It represented a new era in gun violence prevention advocacy in which we really started to look seriously at how to bypass the Republican obstruction of gun safety legislation in Congress,” said Chelsea Parsons, the vice president for gun violence prevention at the Center for American Progress, a left-leaning think tank. “We know even more now about the potential opportunities that exist for nonlegislative approaches to addressing different aspects of gun violence.”

So what, exactly, could Biden do without the support of the Senate? Here are some options for using existing laws and the enforcement power of the executive branch.

Implementing an “all-of-government” approach to gun violence reduction

On Day One, Biden could sign an executive order creating an interagency task force on gun violence prevention. Such a task force could bring together the White House, the Department of Justice, the Department of Health and Human Services, and any federal agency that touches gun violence with the goal of coordinating the national response.

“Every federal agency that may have a stake in at least one aspect of gun violence, coming together in an effort that’s coordinated by the White House, and that has the imprimatur of White House importance, to really from the beginning say: ‘What is this problem? What exactly does it look like? How does it impact different communities, and what are the levers that we have in the federal government to be able to better address this problem?’” Parsons said.

Such a coordinated, government-wide approach to combating gun violence has never been done before, Parsons said. “I think it would be a really meaningful, early step that would set the administration up to be able to develop a strong plan for addressing violence,” she said.

Reinvigorating the Bureau of Alcohol, Tobacco, Firearms, and Explosives

One of the president’s most powerful tools is manning the executive branch through political appointments and personnel choices. For years, the ATF has been floundering without a permanent leader and with an inadequate budget. Since 2006, the agency has had only one Senate-confirmed director who served from 2011-2015. It’s the only federal agency with the authority to regulate gun manufacturers, importers, and dealers.

“At a minimum, it’s crucial to nominate and confirm an ATF director who will promote gun violence prevention values and will really prioritize the regulatory oversight mission of that agency, which is something the agency really has fallen short on in recent years,” Parsons said.

Biden’s platform does not stop with new, more focused leadership. He has said he will direct his attorney general to deliver within the first 100 days a set of recommendations for restructuring the ATF and related Justice Department agencies to most effectively enforce gun laws, including by increasing the frequency of inspections on ATF-licensed gun dealers.

Part of the solution could be directing the ATF to reassess the type of investigations it focuses on. A recent analysis of the agency’s budget found that it disproportionately pursues issues best addressed elsewhere, duplicating the efforts of other federal, state, and local law enforcement agencies. “This is obviously important work, but it is also work that is being done by the FBI and DEA and local law enforcement,” said Parsons, who co-authored the CAP report. “ATF has a unique jurisdiction when it comes to providing regulatory oversight of the gun industry and is uniquely situated to develop interstate gun trafficking investigations.”

Even if he prioritized the ATF’s budget, Biden’s efforts at reforming the agency could be hampered by a lack of money. The president-elect has promised to seek additional funding for the agency and the Justice Department, though that would require approval in Congress and Republicans have historically opposed upping the ATF’s budget.

An overhaul of how the ATF classifies National Firearm Act weapons

The National Firearms Act subjects certain types of weapons and accessories — machine guns, short-barreled shotguns and rifles, and silencers — to heightened regulation. The ATF determines exactly which models, components and accessories should qualifies. Under new leadership, the agency could review its previous determinations and reclassify firearms and components teetering on the line of being considered an NFA weapon.

Bump stocks, accessories added to rifles with the potential to replicate the firing action of a fully automatic weapon, are a recent example. After a gunman used rifles equipped with bump stocks to shoot more than 500 people at a 2017 Las Vegas music festival, the ATF, under heavy public pressure, reclassified the accessory as constituting a machine gun under the NFA, effectively banning their sale in the United States.

In the past, the ATF has taken a lax approach, a Center for American Progress report found, deferring to manufacturers’ stated descriptions of firearms and accessories for determining if they qualify for NFA restrictions. The Trace has reported on the proliferation of barely legal accessories like pistol braces, which can effectively turn a handgun into a short-barreled rifle, and models like the Shockwave shotgun, which narrowly eludes the definition of a short-barreled shotgun.

Reviewing firearms and components on the basis of their potential uses instead of their stated purpose of the manufacturer would be a start. As would making the process more transparent by publicly releasing determinations instead of sending them directly to manufacturers. “That’s something incoming leadership at ATF should really take a strong look at, because you see the industry really innovating to evade the NFA,” Parsons said.

Data collection and research

In order to truly understand the workings of America’s gun violence problem, you need data, but there’s not much high-quality data available. There’s currently a two-year lag on data from the Centers for Disease Control and Prevention on gun deaths, no reliable data on the number of nonfatal gunshot injuries that happen every year, and no up-to-date, reliable nationwide database of crime statistics. The Biden administration could direct agencies to more efficiently collect and publish data, and prioritize data related to gun violence.

Last year, Congress set aside $25 million in funding for gun violence research, the first time Congress appropriated taxpayer money for that purpose in two decades. Having the funding appropriated for research at the CDC and the National Institutes of Health was a win for gun violence prevention groups, Parsons said. “But, you know, there’s a lot more that the federal government can do as well to facilitate that kind of research to make data more available,” she said. “And to use the authority that these agencies have to really help us better understand the scope of this problem.”

One possible avenue would be to get the FBI to collect data on nonfatal shootings as part of its Uniform Crime Reporting program. Biden has also said he will direct the ATF to issue an annual report on firearms trafficking to provide officials with information to better identify strategies for curbing firearms trafficking. The ATF hasn’t released such a report in more than two decades.

Cracking down on untraceable “ghost guns”

Homemade “ghost guns” pose a problem for law enforcement after a crime has been committed. These weapons are devoid of serial numbers or other identifying markings that enable them to be tracked to their maker, seller, or original owner. Despite their frequent use in mass shootingsshootouts with police, and other crimes, ghost guns remain legal in the U.S. and can be made without a background check.

While it might be difficult to ban or prohibit ghost guns through executive action alone, there are proposals on how the ATF could use its rulemaking authority to regulate the parts needed to assemble homemade weapons. One, from Everytown for Gun Safety, would see the ATF requiring the manufacturers of ghost gun parts to stamp them with serial numbers, and subject buyers to background checks. “Ideally, we’d be able to pass legislation to take care of it. But in the absence of that, this is something that can certainly be addressed through rulemaking,” Parsons said.

Banning the importation of assault weapons

While banning the manufacture and sale of assault weapons would require legislative action, the executive has significant authority — and, in fact, a legal obligation — to regulate the importation of firearms from abroad under the Gun Control Act of 1968. Biden could use that authority to restrict the importation of assault weapons.

That law requires the Treasury Department to restrict the importation of firearms unless they are determined to be “particularly suitable for or readily adaptable to sporting purposes.” Since 1989, under Republican President George H.W. Bush, the importation of certain semiautomatic weapons with military configurations has been banned. And in 1998, the Treasury Department and ATF under President Bill Clinton expanded that definition to include semiautomatic weapons with detachable, large-capacity magazines.

But those restrictions have not been aggressively enforced, a 2011 Senate report found, noting that many “military-style, nonsporting rifles have flowed into the United States civilian market.” Biden has said he will use his executive authority to ban the importation of all assault weapons by expanding the list of weapons – and weapon components — considered not suitable for sporting purposes.

Gun rights groups fear he will follow through on that promise. “Unfortunately, the current legislation is written so that the president has the power to decide what’s a sport firearm. And what can be imported into the United States,” said Mark Barnes, a lawyer and gun lobbyist for the National Rifle Association during a Second Amendment conference in September. “And the president holds a great deal of authority, not only to ban certain firearms, but also perhaps gun parts as well.”

Would any new gun laws get through a GOP-controlled Senate?

There are also some modest laws that could have a chance even if the upper chamber has a Republican majority.

In 2019, an expanded background check bill sponsored by Republican Senator Pat Toomey of Pennsylvania and Democratic Senator Joe Manchin of West Virginia nearly made its way out of Congress and to the desk of President Trump, who signaled he would sign the bill. That is, until negotiations stalled amid Trump’s impeachment. With a Biden administration more focused on expanding background checks, the Manchin-Toomey proposal — or something similar — could be signed into law.

“With pressure from the House… and with President Biden not only supporting that legislation but taking action in his own right through the executive action process and federal rulemaking, I think it just kind of compounds the message that Senate Republicans can’t get off the hook,” said Adzi Vokhiwa, director of federal affairs for the gun violence prevention group Giffords.

Some of Biden’s other proposals, like $900 million in funding for community gun violence prevention programs and adequate funding for existing background check programs, may also have a decent chance in a Senate with a slim Republican majority.

“The gun lobby and the NRA no longer have a stranglehold on our elected officials,” Vokhiwa said. “Unfortunately, there are a few in the Senate, particularly Senate Republicans, who still seem to think that they need to be beholden to the gun lobby. But I think that’s just evidence that they’re out of step with the American public who, by and large, want a government to take action on gun violence and what elected officials to pass legislation and take executive action to save lives.”