If
Russia occupies the border areas of eastern Ukraine to defend an autonomous zone and annexes the Crimean Peninsula, how could the Ukrainian military respond?
Very carefully. Good grief, the deployments are still based on Soviet patterns. Are 8th and 13th corps really going to be in the third echelon of a drive on the Rhine?
Specifically, the Ukrainians need to avoid fighting in the east because the damage and casualties might lead locals to look to the Russians to protect them and might change sentiments from political opposition to separatism.
If the Russians want to fight in the east, make the Russians move west and extend their supply lines and deplete their forces as they leave garrisons in their wake.
And make their claims of fraternal assistance to ethnic Russians obviously a fraud.
If Russia annexes Crimea, the Ukrainians should focus their military efforts on driving the Russians from that peninsula, or at least besieging the Russians in Sevastopol.
By focusing on the most blatant violation of Ukraine's territorial integrity, ethnic Russians might be persuaded to side with Ukraine.
The Ukrainians don't have a lot to work with. They have just 63,000 in the army and about 80,000 paramilitary troops. Plus 3,000 naval infantry.
The army is spread out across Ukraine:
6th Army Corps, Dnipropetrovsk (Units based in the area of the Southern Operational Command)
17th Tank Brigade, Kryvyi Rih
25th Airborne Brigade, Cherkaske
28th Guards Mechanised Brigade, Chornomorske
92nd Guards Mechanised Brigade, Chuhuiv
93rd Guards Mechanised Brigade, Cherkaske
55th Artillery Brigade
8th Army Corps, Zhytomyr (Units based in the area of the Territorial Directorate "North")
1st Tank Brigade, Honcharivske
30th Mechanized Brigade, Novohrad-Volynskyi
72nd Mechanized Brigade, Bila Tserkva
95th Airmobile Brigade, Zhytomyr
26th Artillery Brigade, Berdychiv
3rd Army Aviation Regiment, Brody
13th Army Corps, Rivne (former Soviet 13th Army) (Units based in the area of the Western Operational Command)
24th Mechanized Brigade, Yavoriv
51st Mechanized Brigade, Volodymyr-Volynskyi
128th Guards Mechanized Brigade, Mukacheve
11th Artillery Brigade, Ternopil
7th Army Aviation Regiment, Novyi Kalyniv
Add in the 79th Airmobile Brigade and a surface-to-surface missile brigade
Note that these "corps" are really division-sized formations.
There are reservists, but on the Soviet pattern they use, their memory of military skills will range from hazy to "I was in the military?"
The Ukrainians do have lots of armored vehicles and artillery, although I don't know how much of it is in working order. I'm not sure what to make of 5 tank divisions in storage. Could they possibly be manned in war? I'll assume that the Ukrainians can equip their active forces and at least have some heavy stuff for mobilized reservists and not just have a force of light infantry.
Give the Ukrainians credit for 100 reasonably modern fighters and 70 ground attack planes. Plus a decent amount of transport planes and some helicopters.
The navy is almost non-existent. The most interesting are 2 large air cushion vehicles capable of carrying up to 230 troops, a tank platoon, or a company of armored personnel carriers. This is from 2008 information. I don't see these vessels mentioned more recently. But the navy is irrelevant.
The first thing the Ukrainians need to do is call up reservists and equip as many as they can, and send them to the cities of Ukraine. This should be especially done in the north facing Belarus and in the east along the Dnieper River and down to the Sea of Azov.
The Ukrainians need these road blocks because the army will be thin on the ground on most of the border.
Ukraine's Sixth Corps should keep two mechanized brigades and a paratrooper brigade in the east to screen the Russians sitting in Kharkov and Donetsk, and points in between. Paramilitary police will support.
But these forces should not be too far forward in the ethnic Russian zones.
As information operations and diplomacy work on the communities east of the Dnieper and get them to throw in with Kiev, Ukrainian police units can move east carefully to absorb new additions of loyal territory.
Eighth Corps should keep all of its forces but an artillery brigade. This leaves a tank brigade, two mechanized brigades, an aviation regiment, and an airmobile brigade to protect Kiev and screen the north and northeast. Add in other police units.
As reserves are mobilized, some of this corps could be used as a reserve for the east or the main front in Crimea.
Thirteenth Corps will lead the offensive against Crimea.
It will move with its aviation regiment, three mechanized brigades, and an artillery regiment, for the narrow isthmus that leads to Crimea.
Sixth Corps units somewhat near the isthmus--a mechanized brigade, a tank brigade, and an artillery brigade, will join with an artillery brigade from Eighth Corps and the separate airmobile brigade and separate missile brigade, to move on the isthmus quickly, where they will be attached to 13th Corps.
As many air defense units that can be scraped together should be earmarked for covering Crimea to prevent Russian air reinforcements and resupply.
So the total will be 6 maneuver brigades, and aviation brigade, two artillery brigades, an airmobile brigade, and a missile brigade. Call it 30,000 plus whatever reservists can be sent in its wake.
And send 20,000 paramilitary police to garrison the pro-Russian areas along the line of communication.
Mobilized reservists can be sent to help control rear area strongpoints along the lines of advances as 13h Corps pushes south.
The idea is to move as quickly as possible to either drive the Russians from Sevastopol, or, if that isn't possible, to block the Kerch Strait and push artillery and the missile brigade to within range of the base to bombard the Russian fleet in port and facilities there--especially airfields.
Air defense units would attempt to isolate the base from air reinforcements.
Ukraine should burn their air force if they have to in order to enable the army to push south. You don't get points for losing a war and having stuff left over.
This applies to the navy, too, but I have little hope it could do much. If they can lay some mines around Sevastopol and use their limited amphibious assets to support their marine battalion in blocking the Kerch Strait until army or reservists can move up in support, that's above and beyond, under the circumstances.
The Ukrainian army would be nearly outnumbered by the notional 15,000 Russian paratroopers and 10,000 paramilitary troops sent to back the 3,000 naval infantry already in Sevastopol.
But if the Ukrainians can move faster than the Russians, the Russians might not be able to deploy quickly away from the airfields or from distant Kerch after crossing from Russia. Especially if Ukrainian air defense and fighter assets can throw up a credible screen (and if Ukraine's marines can tear up the roads and slow down this attempt to reinforce Sevastopol).
And the Ukrainians would have the advantage in firepower and speed, with a largely mechanized force. Much of the Russian force would be pretty light, with only lightly armored vehicles in support.
The Ukrainians would need to get the missiles in action against Russian ships in port.
Of course, this is all a paper exercise. I have no idea if the Ukrainian military is in any shape to move quickly and go on the offensive. The units are poorly deployed for post-Cold War missions. I suspect they couldn't really mount a credible offensive.
But what else could they do? Seal off Crimea and hope the Russians don't want to keep it?
Even if the Ukrainians can't capture Sevastopol, if the Ukrainians can put the base in range of artillery assets, Ukraine might be able to leverage the Russians out of eastern Ukraine in exchange for giving up the generally hostile region of the Crimea where ethnic Ukrainians are few.
But this is the only real military option that seems likely to have a chance of working. On paper, I admit.