You have to remember, a nuke is worth a lot of money to people like bin Laden. And Ukraine is one of the poorest places outside Africa. Right now, the average yearly salary in Ukraine is $750. That's about what my monthly electric bill is in the Summer, thanks to Gray Davis. Not much to live on for a year.
If I'd been a guard on one of the mobile SS-19 launchers based in Ukraine after the Soviet armed forces broke up, I'm pretty sure some evil little thoughts would've started going through my head, like should I be a good little sentry and starve to death, or should I talk a couple of my buddies into helping me unscrew one of those warheads so we can auction it off to some Jihadi with more money than sense? A nuclear warhead would sell for a lot of rubles in places like Riyadh, or Sana'a, or Islamabad (this was back before Pakistan could make their own nukes).
A lot of bad Hollywood thrillers got made out of that scenario, but it didn't happen. The official line is that Ukraine destroyed its last SS-19 at Khmelnytsky airbase on June 5, 1998.
If anything was going to happen in Ukraine, it would've happened back then in the crazy days after the USSR dissolved. Instead whoever's running the country gave up the nukes that put them in the world-power club. So you have to figure Ukraine is run by pretty easygoing types who just want bribes, not power.
Even if they wanted a war with Russia, I'm not sure whether Ukraine could manage it. Russia's not doing too well down in Chechnya, but at least they've got a real army and air force, real vets. I'm not sure Ukraine does. If you track the Ukrainian Army since independence, you see it's one of those bloated draftee forces designed for WW II, with too many grunts and way too few techies. In 1991 Ukraine had 500,000 troops. Now they're below 300,000 and they'd like to go much lower. There just isn't much use for cannon fodder any more.
Russia's got the same problem: too many troops and not enough money, tech support, training, or decent officers. Russia keeps making noise about switching to a small, professional army. It's not going to happen soon, but it does show you one thing, they don't feel ready to fight. Chechnya's so small they can do it without straining too hard, a little low-intensity counterinsurgency sideshow. They can keep that going with a few mercenaries, which is what they're doing right now. There's good money to be made in the smuggling business for officers and contract soldiers.
Fighting Ukraine in a conventional war would be a whole nother thing. It wouldn't make any sense -- be more like a 1943 reenactment than a real battle, because the both armies were designed to re-fight WW II. And since they're both Soviet knockoffs, it would be like fighting yourself in the mirror.
The more I read about Russia and Ukraine, the more they both look like dead-tired old boxers going into the 12th round. They've got no birthrate, no money, no big rallying cry. A new poll shows Ukrainians absolutely don't want to fight and feel a lot of sympathy for the Russians' position. Not the kind of wild-eyed berserkers you'd want to take into a rumble.
And the guys who run the two countries aren't much to get excited about either. Kuchma, who runs Ukraine, plays rough with internal opposition but wags his tail whichever way NATO tells him to, all the time sucking up to Russia whenever NATO's distracted by other matters, which is most of the time. Putin, the fish-faced little judo-ka who runs Russia, has all the war he needs in Chechnya. He doesn't need trouble with people who are pretty much identical to Russians, only poorer. Russians, see, make a whopping $1,800/yr. Not much, but about 2.5 times what Ukrainians make. So the biggest threat to Russia from Ukraine is the flood of cute Ukrainian girls who bring down the price per hour in the Russian prostitute markets. But you eXile types know more about that than I do. Only Russian girl I ever got to look at was Natasha on Bullwinkle.