First, it’s important to recognize that this probably isn’t a problem. The quarter-to-half number isn’t of all illegal guns in these countries, or all guns used in crimes, but of all guns submitted to the ATF for tracing. Given that different jurisdictions have different models available for sale and use, this tool is usually used for confirmation of already existing belief – it should be surprising that this is so low. Moreover, just because a gun was traced to the United States doesn’t mean that it came from a straw purchase : most guns tied to crime came from theft rather than unlawful purchase, sometimes from armories or police and military sources.
Likewise, when there was an actual straw purchase rather than a theft or lost firearm, those traces do incriminate bad actors among FFLs and purchasers. The BATFE can trace a cache of seized guns. Not only in the sense that a serial number tells the BATFE exactly what FFL last had the gun before selling it to individuals, or that in turn gives the BATFE a
signed confession form 4437 with exact name and signature of a purchaser, but also in the sense that stings and informants are exceptionally common. Proven bad behavior absolutely can end up in revocation of a license, or even imprisonment, so on.
There are some technical things that can be pushed. Customs and border enforcement is a joke in most sadistic way possible, right now, coming down on the law-abiding or mere paperwork mistakes like a load of bricks while not touching severe bad actors. Some of that’s a political matter that’s a really hard problem to solve: if you could talk people into not taking frustrations related to illegal immigration out on legal applicants, there’d be far grander issues we could be focused on.
Other aspects are technical, though. There’s a lot of sensors out there that work in theory, but are either so unreliable, so manpower intensive, or so expensive that they’re only used for minuscule fractions of customs work. But at the same time, it’s an issue that will also be getting harder to fight, as drones, remote vehicles, and ultra-light aircraft become more and more available to smugglers.
But this doesn’t really solve the problem of homicide in these countries. Places with similar levels of civil unrest and no obvious links to American firearms still have awfully high death rates, either by getting guns in other manners, or falling back to other means of slaughter, or both. We don’t really know what processes a low-income low-stability country needs to take in order to improve those situations. And fixing that is both a hard problem and one that Americans are unusually ill-fitted toward. While blaming American foreign policy for the current state of Honduras is a little much, the Contras are remembers and not remembered well.