Here is my amateur armchair generalizing, copied from Facebook: I'm almost certain it won't happen, but it's always fun to consider these what-if military scenarios. Namely, Ukraine vs. Russia. In terms of numbers, it will be about 100K vs 150K - Russia has more, of course - 300K in the ground forces - but can only devote a certain percentage of its forces to one theater (so divide by two for air and armor too). Ukraine will of course try to call up reservists, but their military worth is negligible and in any case the reported response rate (1.5% from the Orange provinces) is minimal anyway. Most of Russia's soldiers here will be kontraktniki; most of Ukraine's soldiers are its last crop of conscripts, halfway through their one year draft, and a sprinkling of professionals. As many people have pointed out, the loyalties of these troops - especially in the east - are questionable. Even a few cases of desertion can wreck morale across the board. For all intents and purposes Ukraine now has no navy. It has 120 modern fighters, but of these, only 40 can be classed as active. Russia has 500, of which almost all are active. Due to budget problems, Ukrainian pilots have enjoyed fewer flight hours than Russian ones, and as such will also be less experienced. Russia will have total air superiority after the first few days. Tanks are the one area in which Ukraine isn't totally outmatched. Ukraine has around 350 of what can be considered active, modern MBT's. Russia has 1,300, plus a further 1,500 upgraded T-72's. Ukraine also has many T-72's, but they are all rusting away in storage and will be unusuable. It does have 700 active upgraded T-64's, yet even upgraded, they are still rather obsolete. The critical big unknown is Ukraine's air defense. If it holds its own, then Ukrainian and Russian armor can clash on equal ground, at least for some time. Georgia's air defense, likewise Soviet legacy, wracked up an impressive (for their small scope) set of kills in 2008. A lot will depend on whether the Russians have managed to draw lessons from that episode. If however it turns out to be ineffective, then Ukraine's armor will consist of smoking hulks of metal within two weeks, and Russia's entrance into Kiev within the month. I am assuming no NATO intervention, which is politically very unlikely even in this extreme case. In any case, it will take months to effect the necessary buildup, by which time - even in the best case scenario for Ukraine - the campaign will have been long over.