They likely either still have a nuke or two, or have the means to make one. Problem for Ukraine is, how do they use it? If one was left over from the
disarmment, then this would make Kyiv guilty as well of not fullfilling the agreement, so far they are keen on impressing the West in regards to their
eagerness to stick to the status quo.
If they should make a new nuke, they can't just tell Russia to "leave E. Ukraine and crimea, or we'll nuke you." because Russia would consider this a
direct threat, and Putin would be justified in taking out their nuclear facilities, using either nuclear or conventional means. The EU, and possibly
the US may also condemn Kyiv for taking the nuclear route.
Still, when push comes to shove, I couldn't hardly blame them. Ukraine is fighting an aggressor several times more military capable than themselves.
For all we know, Ukraine has a couple nukes, but it waiting until the last possible second to threaten the use of them...but to disclose this in a
warning to Russia, will no doubt trigger a military response. If they were to forego the warning, and just use a nuke, it was for certain trigger a
nuclear response from Russia, and likel cause World War III.
If I were them, and had a nuke, I wouldn't make it public for sure, but I'd also wait until I had no other option other than disclosing this fact.
Only other tactic I can see would be a terror attack against Russia, similiar to what Russia is doing now, where they drop a dirty bomb, but don't
take credit for it...but its likely this would also escalate, where Russia would blame Ukraine and possibly the West, again, triggering a nuclear
Personally, I think they got a nuke, or can make one easy enough. If North Korea could make a few nukes under heavy sanctions and limited funds, i'm
sure Ukraine would have no problem in doing this. They know how to do it, and likely have the facilities left over from the cold war to do it with. If
there were to happen to be a leftover nuke or two in Ukraine, doesn't matter if it works or not, they can still harvest the radioactive material to
build new ones. In either case, they can probably (and possibly have) build new ones from scratch if they chose to do so, and it would be above top
secret. The US didn't exactly have nuke facilities in place when Fat Man and Little Boy were built. Where there is a need, there will be a
edit on 27-7-2015 by JonStone because: (no reason given)