It is unlikely that we will see new nuclear powers. It's not an easy job. We can be sure that Israel or North Korea won't give up, but that does not mean they are going to use the weapons or there will be a full-blown intercontinental war. Looking at current progress in space tech, in 30-40 years the ultimate WMD will be kinetic space weapons anyway.
North Korea and South Africa* getting nukes are both independent proofs that it's not hard for a nation to get nukes. I've seen credible commentators suggesting Ukraine itself is only months away, if it chooses that path.
Less credibly, because the Russian government says a lot that isn't really true, Medvedev has been quoted saying "a number of countries are ready to directly supply Iran with their own nuclear warheads".
Once you've got a fission bomb, by all accounts it's not that hard to use it as a primary to power a fusion bomb.
A single 1 MT bomb detonating at low orbital altitude above central USA would likely cause enough physical damage to the power grid to kill 60-90% of the population within a year, even with no shockwave getting anywhere near the ground.
> North Korea and South Africa* getting nukes are both independent proofs that it's not hard for a nation to get nukes
Define „hard“ then. Both started early in 1960s, both had access to uranium (North Korea is actually mining it - not every country can do that), both used foreign support for their nuclear programs. Neither achieved ICBM range to deliver nuclear warheads to any location on this planet or had submarine component. Ukraine may have theoretical ability to design and produce nuclear weapons, but it is a technologically advanced nation far ahead of many developing countries and it is not going to have resources for a nuclear program any time soon being heavily dependent on foreign aid.
