Following the recent mass shooting in Orlando, and the shootings in Minnesota and Dallas, the sharp political divisions over gun control within the U.S. are once again on display.
In June, House Democrats even staged a sit-in to advocate for stronger laws.
There is some evidence that more restrictions can reduce gun violence, but another recent shooting highlighted some limitations of regulation.
British Member of Parliament Jo Cox was murdered with a 'makeshift gun' despite the United Kingdom's restrictive gun-control laws.The threat of self-manufactured firearms is not new, but a critical barrier is collapsing.
Nevertheless, participants recommended a number of policies, such as more rigorous intellectual property laws, to counter the evolving threat of unregulated 3D-printed weapons.
These types of policies will become increasingly important as at-home manufacturing of firearms weakens traditional gun control regulations such as those focusing on the buying and selling of weapons.
The danger goes well beyond firearms.Countries seeking to develop nuclear weapons could use additive manufacturing to evade international safeguards against nuclear proliferation.
Traditional nuclear weapon control efforts include watching international markets for sales of components needed for manufacturing a nuclear device.
Additional measures place restrictions on the types of technology nuclear capable states can export.
Additive manufacturing could avoid these efforts by letting countries make the equipment themselves, instead of buying it abroad.
Research into this threat led nonproliferation scholar Grant Christopher to recommend that governments enact export restrictions on certain types of 3D printers.
Nuclear policy experts Matthew Kroenig and Tristan Volpe proposed other approaches to limit additive manufacturing's dangers to nuclear security.
One way could be increasing international cooperation to regulate the spread of 3D printing technology.
Beyond regulating the hardware, governments and industry professionals can also work to more effectively secure the files needed to build components for weapons of mass destruction.
Arms control analyst Amy Nelson points out that the risk this kind of data will spread increases as it becomes increasingly digital.
Terrorist groups and other nongovernment forces could also find ways to use 3D printing to make more destructive weapons.
We argue that despite these groups' interest in using weapons of mass destruction, they don't use them regularly because their homemade devices are inherently unreliable.
Additive manufacturing could help these groups produce more effective canisters or other delivery mechanisms, or improve the potency of their chemical and biological ingredients.
Such developments would make these weapons more attractive and increase the likelihood of their use in a terror attack.
The worst threats 3D printing poses to human life and safety are likely some distance in the future.
However, the harder policymakers and others work to restrict access to handguns or unconventional weapons, the more attractive 3D printing becomes to those who want to do harm.Additive manufacturing holds great promise for improvements across many different areas of people's lives.
Scholars and policymakers must work together to ensure we can take advantage of these benefits while guarding against the technology's inherent dangers.