> they could have an arsenal that’s functional as a deterrent in months, if not weeks
Japan is what's called a threshold/latent nuclear power. These are countries with the ability to build nuclear weapons immediately, but haven't turned the switch yet.
Taiwan, Iran, Canada, Germany, Netherlands, Brazil, Mexico, and South Korea are other threshold powers, and Saudi and the UAE are pressing for plutonium enrichment capabilities in the next few years as well.
Generally speaking, a country with a space program and a civilian fuel enrichment program can be safely assumed to be a latent nuclear power.
Japan is what's called a threshold/latent nuclear power. These are countries with the ability to build nuclear weapons immediately, but haven't turned the switch yet.
Taiwan, Iran, Canada, Germany, Netherlands, Brazil, Mexico, and South Korea are other threshold powers, and Saudi and the UAE are pressing for plutonium enrichment capabilities in the next few years as well.
Generally speaking, a country with a space program and a civilian fuel enrichment program can be safely assumed to be a latent nuclear power.
https://en.m.wikipedia.org/wiki/Nuclear_latency