This article originally appeared in The Trace.

President Barack Obama is ushering in the new year with his sights set on gun reform. On Monday, the White House began the rollout of a suite of new executive actions designed to curb firearm-related violence. The move is a presidential counterpunch to a Congress unwilling to pass tougher gun laws, and represents Obama’s most significant effort to alter gun policy since an earlier display of executive power following the Sandy Hook massacre.

Obama officially announced the executive actions during remarks late Tuesday morning, but a fact sheet circulated by the White House beforehand sketched out the package. It includes a plan for the FBI to increase the number of federal gun background check examiners and staff by 50 percent; a proposal to hire an additional 200 federal agents and investigators to focus on gun offenses and regulations; and a directive to the Departments of Justice, Defense, and Homeland Security to develop research agendas for firearms safety and possible procurement strategies for smart guns.

The centerpiece, however, is an action destined to draw pushback from the gun lobby, as well as questions from those new to the gun debate: a push to ensure that persons “engaged in the business” of selling firearms register as licensed dealers. How does the law currently work, and what is the White House hoping to change? Below, a breakdown.

What’s this “ENGAGED in THE BUSINESS” business?

Gun sellers fall into two categories: federal firearms licensees (FFLs) and private sellers. FFLs are regulated by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), and conduct background checks on their customers. The same rules do not apply for private sellers who, in 32 states, operate without government oversight, and are not required to vet their purchasers to ensure that guns stay out of the wrong hands.

Under existing law, there’s no expectation that a gun owner who occasionally sells a weapon from his or her personal collection—to offload an under-loved model, make room in the budget or gun cabinet for their next purchase, or set up a friend new to shooting—register as a licensed dealer. But anyone who sells guns with the primary goal of bringing in income, and “devotes time, attention, and labor” to that pursuit, is considered “engaged in the business.” And that person is supposed to register as an FFL.

Why is the current definition a problem?

Because it leaves the question of who is “engaged in the business” open to broad interpretation—and by extension, makes the lawsubject to abuse. Private gun sellers can move large quantities of firearms while claiming to be hobbyists, not retailers, and never subject their customers to safety checks nor themselves to ATF oversight. Reform advocates have called for clarifying the “engaged in the business” standard to set more objective criteria that would in turn drive more sales out of the unregulated private market and into the background check system. As things stand, case logs indicated that persons who avidly peddle a significant number of guns are not merely cutting corners while selling to lawful owners, but instead have a tendency to be engaged in trafficking to the black market or flouting other gun restrictions.

How “engaged in the business” is defined also matters for law enforcement officers and prosecutors: It’s one of the tools they use to combat arms traffickers, and it has proved to be a less than well-honed one. In November, an analysis by Everytown for Gun Safety (a seed donor to The Trace) found that federal prosecutors accepted only 54 percent of “engaged in the business” cases in 2011 and 2012. (In comparison, 77 percent of drug trafficking cases were accepted for prosecution during the same time period.) Of those firearms cases that made it to court, one-third were dismissed by a judge, and half of the cases that went to trial resulted in an acquittal. With a clearer standard, investigators and prosecutors might be more inclined to go after sources of crime guns, and more successful when they do.

The ATF told The Trace in October that as of that month, it had only prosecuted 57 cases in 2015 for illegal engagement in the gun business. Those who do manage to run afoul of this law are usually the most flagrant offenders. In one case, a California cop used his police credentials to not only sell guns without an FFL, but to sell gun models banned in California. In another, a former Texas judge sold guns without a license despite a warning from the ATF. A Chicago man boasted to an informant of the trips he made to gun shows in Indiana, where he stocked up on “duffel bags full of guns” to sell at a mark-up back home.

Does Obama’s move close the “gun show loophole”?

No. It would more accurate to say that it shrinks it—but how much it shrinks it won’t be clear until further details emerge. Reports had indicated that the Obama administration might set a sales volume past which a seller automatically qualified as “engaged in the business,” but the executive action Obama announced Tuesday does not include such a numerical threshold. Instead, the White House says that sales quantity is one of the factors—along with how long guns are held before being sold, and how much a seller markets him- or herself—that will go into requiring that a seller be licensed.

How are the presidential candidates reacting?

Predictably. Chris Christie and Jeb Bush slammed the actions as executive overreach—with Christie saying the directives were evidence Obama acts like “a dictator,” and Bush calling them “quite dangerous.” Donald Trump promised that he would “unsign that [action] so fast.” Ditto Marco Rubio and Ted Cruz, with the latter challenging that the presidential “pen has got an eraser.”

The Democratic candidates, meanwhile, are welcoming the move. Bernie Sanders, who has taken heat for his gun-friendly votes in the past, praised the action on a political talk show. Hillary Clinton, who vowed in August to take executive action against illegally “engaged in the business” sellers herself if elected, tweeted that she was “so proud” of the president.

Late last year, some gun violence prevention activists close to the Clinton campaign told The Trace that the candidate would likely find political utility in executive action on guns by Obama. Republicans’ uniform contempt for Obama’s package, and their vows to undo it, mean that should Clinton gain her party’s nomination, she’ll be running against a rival who has effectively come out against the very popular background check system.

What are the risks of this approach?

In opposing Obama’s executive actions, Republican presidential candidates warn that his reliance on presidential authority flouts the US Constitution. The legal scholars at the American Constitution Society have begged to differ. But as the executive actions are fleshed out, that may not be the question on which the fight turns.

“Executive action” is a catch-all phrase for policy pronouncements originating from the White House; executive orders are legally binding directives, like the Emancipation Proclamation. Put another way: The president could issue an executive action recommending that his employees spend time with family over the winter holidays, or instead give an executive order declaring the office closes early on Christmas Eve (as Obama did this past December).

Obama’s new executive actions on background checks do not approach the level of an order. Rather than a hard-and-fast regulatory change—which can take longer to develop than Obama has left in his presidency—they represent less formal guidelines that the ATF will implement for gun sales. Which means that Obama may wind up facing criticism not just from those who think he’s overstepped, but those who could conclude he has not gone far enough.

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