The technical argument is that these are potentially weapons of mass destruction, and the international community has thus far banned all other weapons of mass destruction.

What makes these different from previously banned weaponry is their potential to discriminate. You could say, “Only kill children,” and then add facial recognition software to the system.

Moreover, if these weapons are produced, they would unbalance the world’s geopolitics. Autonomous robotic weapons would be cheap and easy to produce. Some can be made with a 3-D printer, and they could easily fall into the hands of terrorists.

Another thing that makes them terribly destabilizing is that with such weapons, it would be difficult to know the source of an attack. This has already happened in the current conflict in Syria. Just last year, there was a drone attack on a Russian-Syrian base, and we don’t know who was actually behind it.

Why ban a weapon before it is produced?

The best time to ban such weapons is before they’re available. It’s much harder once they are falling into the wrong hands or becoming an accepted part of the military tool kit. The 1995 blinding laser treaty is perhaps the best example of a successful pre-emptive ban.

Sadly, with almost every other weapon that has been regulated, we didn’t have the foresight to do so in advance of it being used. But with blinding lasers, we did. Two arms companies, one Chinese and one American, had announced their intention to sell blinding lasers shortly before the ban came into place. Neither company went on to do so.

Your petition — who was it addressed to?

The United Nations. Whenever I go there, people seem willing to hear from us. I never in my wildest dreams expected to be sitting down with the under secretary general of the U.N. and briefing him about the technology. One high U.N. official told me, “We rarely get scientists speaking with one voice. So when we do, we listen.”