The United States Federal Bureau of Investigation is examining Wednesday's mass shooting in San Bernardino, California, as a possible terrorism case, the New York Times reports. Officials haven't ruled out other motives, but "the suspects' extensive arsenal, their recent Middle East travels and evidence that one had been in touch with people with Islamist extremist views, both in the United States and abroad, all contributed to the decision to refocus the investigation," according to the Times.
The case brings up an ongoing debate about American gun laws: whether people in the Terrorist Screening Database, which is the U.S. government's watch list of known and suspected terrorists, should be allowed to buy firearms. Government agencies nominate people for inclusion on the list, and officials at the National Counterterrorism Center and the Terrorist Screening Center decide whom to actually add. (To be clear, there's been no reporting about whether the San Bernardino suspects had ever been on the watch list. Authorities say the four guns the couple used in the shooting were purchased legally, though not all were purchased by the suspects).
Right now, inclusion in the watch list isn't reason enough to deny someone the ability to buy a gun. Gun-control proponents call this fact the "terrorist gap." We don't know of any serious proposals for automatic denials based on inclusion in the watch list, but some lawmakers have advocated for closer scrutiny of potential gun buyers who are found to be on the list. The National Rifle Association, on the other hand, opposes laws aimed at strengthening officials' use of the Terrorist Screening Database for denying gun purchases.
Below, our quick primer on the issue:
HOW IS THE WATCH LIST USED NOW IN FIREARMS SALES?
Licensed gun dealers in the U.S. must perform background checks on potential buyers. (Of course, those who buy from private sellers often don't have to undergo any background screening.) Part of the so-called "federal background check" involves seeing if the buyer is in the Terrorist Screening Database. If he or she is, the FBI is then notified, and staffers at the National Instant Criminal Background Check System (NICS) are called to investigate.
Most of the time, the sale still goes through. Between 2004 and 2014, 91 percent of gun-buying transactions that were flagged as involving someone on the terrorist watch list were cleared to proceed, the Washington Post reports. That's 2,043 transactions.
Because being on the watch list alone isn't legally sufficient to deny somebody a gun, the NICS investigation has to turn up something else before halting a sale. In a study published in 2010, the Government Accountability Office found that those who were denied a gun were either convicted felons, undocumented immigrants, under indictment, fleeing justice, or mentally ill—all legally sound reasons for stopping a gun sale.
HOW DO PEOPLE END UP ON THE WATCH LIST?
Government agencies nominate people to the list, which agencies share between themselves. The level of evidence agencies need to get someone on the watch list is low enough that the government historically has not used the list to automatically deny people rights and privileges such as entering the country, or getting on an airplane. As with gun buying, being on the watch list usually triggers a more in-depth assessment of how serious a threat the person poses.
There are about 700,000 people on the watch list, a fact that civil-liberties activists have used as evidence that the list likely includes innocent family members and acquaintances of truly threatening people, the Washington Post reports.
WHAT STRICTER RULES ARE PROPONENTS HOPING FOR?
Some lawmakers have proposed additional layers of scrutiny to watch list-flagged gun purchases. One common proposal that's been talked about since at least 2007 revolves around allowing the attorney general the ability to investigate and deny sales. But, the Washington Post reports, "These bills have rarely made it out of committee, in part due to vehement opposition from the National Rifle Association and its allies in Congress."
WHAT ARE THE ARGUMENTS AGAINST STRICTER SCRUTINY?
The NRA opposed previous versions of the bill, claiming the current system worked well to keep terrorists from buying guns. The NRA also thought the bill was "aimed primarily at law-abiding American gun owners," and that "prohibiting the possession of firearms doesn't stop criminals from illegally acquiring them."
WHAT DOES THE RESEARCH SAY?
In its 2010 report on the issue, the non-partisan GAO didn't offer judgment on whether the FBI's current system works well enough, offering only the number of would-be gun buyers who were flagged—and denied—as watch list members. It also offered no recommendation as to whether the attorney general be allowed to investigate cases.