I didn't say unilateral, although I support that as well. The United States is the only country ever to use nuclear weapons, and is also one that I reside in. If I lived in Russia or China, I would advocate for unilateral disarmament in those countries as well. Nuclear weapons are an absolute horror and should be completely eliminated from this planet. The United States (unlike China) does not even have a "No first use" policy -- it reserves the ability to use nuclear weapons aggressively or pre-emptively.
“Hawking's rationale was that humankind would eventually fall victim to an extinction-level catastrophe - perhaps sooner rather than later. What worried him were so-called low-probability, high impact events - a large asteroid striking our planet is the classic example. But Hawking perceived a host of other potential threats: artificial intelligence, climate change, GM viruses and nuclear war to name a few.
In 2016, he told the BBC: "Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or 10,000 years.”