As Ukraine drives Russian forces back, Russian forces pushed back into Russia find themselves in sanctuaries--because Ukraine can't really invade the far larger Russia--able to regroup to return to Ukraine for the fight. Until Russia finds it must rely on even more of those sanctuaries to hold the line. Then things get complicated and dangerous. Even for Ukraine.
Despite Russian claims that it invaded Ukraine to prevent an invasion, Ukraine essentially can't invade Russia (as opposed to limited strike and special forces attacks) despite pushing Russia back on large sections of the front to the border. If it does invade even a little, it gives Putin an easy escape to his military problem by allowing Putin to declare Russia invaded and justify full mobilization--and probably rallying the Russians around Putin. And even Russian use of tactical nukes against Ukrainian units on Russian territory would likely be met with relatively muted outrage abroad.
On the other hand, with Ukraine pushing Russia back to more of the border, Ukraine must defend the borders to prevent Russia from striking back into Ukraine and potentially flanking and isolating Ukrainian forces advancing to liberate more Russian-occupied Ukrainian territory. Although if not trained and equipped, those masses of poorly trained men mobilized are more likely to suffer the fate of the Italian 10th Army in Egypt in 1940.
Some say Russia cannot admit defeat in its war against Ukraine and that Ukraine can't stop until it liberates all of its territory. I imagine Russia's retreat to its own borders on parts of the front will be an interim step before having to admit defeat.
Recall that when Iraq invaded Iran in 1980 to "recover" its territory and ethnic Arab people from Persian Iran, eventually Iran killed enough Iraqis troops to force Iraqi troops back into Iraq itself where it was forced into expensive defensive operations for years. So I imagine Russia can admit a need to retreat--even if it insists the war will go on--if its losses get too high.
Ukraine should learn from that war that trying to attack too much as Iran did for years after pushing Iraq back to the border (more or less) is very dangerous. Rather than declare a defensive victory, Iran tried to crush Iraq. And limited Iranian success in advancing into Iraq led Iran to push too hard and break its own army despite its long advantage of superior numbers, morale, and willingness to die.
The long war ended with the border largely unchanged after hundreds of thousand of dead. That said, I don't know what "too much" is for Ukraine. There are certainly areas that must be liberated for its security or economic health:
Ukraine must regain certain specific areas currently under Russian occupation to ensure its long-term security and economic viability. Ukraine’s ability to defend itself against a future Russian attack requires liberating most of Kherson and Zaporizhia Oblasts. Ukraine’s economic health requires liberating the rest of Zaporhizia Oblast and much of Donetsk and Luhansk Oblasts, including at least some territory Russia seized in 2014. Ukraine’s security would be materially enhanced by liberating Crimea, which would also benefit NATO’s ability to secure its southeastern flank. [emphasis in original]
And part of "too much" could also learn from the Iran-Iraq War when both sides reacted to the stalemate. Each side hit the other's cities and tried to destroy the other's means of financing the war by striking oil exports. The latter eventually brought America and its allies into the war on Iraq's side at sea. And even got the USSR involved a little bit on Iraq's side.
Would Ukraine try to sabotage Russian energy pipelines? Would Russia try to strike NATO logistics support infrastructure for Ukraine in Poland?
Or would Russia attack Elon Musk's Starlink? Could Ukraine rig an anti-satellite weapons to loft up into low-earth orbit from a fighter jet to hit Russian assets?
And don't forget that Iraq resorted to chemical weapons to kill Iranian troops.
Ukraine is fully justified in liberating everything, of course. Russia recognized Ukraine's borders before 2014 and pledged to respect its territory. But the price versus the result is a consideration. The most basic result is making sure Russia can't just rebuild and invade again in the future. Ad infinitum. That's why I think the southern front is so important.
Still, before it gets to the "too much" stage the West might successfully provide an "off ramp" for Russia and Ukraine. Ukraine ends its offensive before it risks its own army; and before Russia cracks as a political entity with all the risks of nuclear war in defense of Russia's territorial integrity or "only" the dispersal of Russian nuclear weapons to more breakaway states. Who will give up nukes as Ukraine, Belarus, and Kazakhstan did when the USSR broke apart, given Russia's invasions of Ukraine?
But we're not at that stage of an opportunity to end the war short of the territorial destruction of either Ukraine or Russia.
And who knows, maybe the beatings with the clue bat will provide Russia with a moment of clarity about the true threats to Russian territorial integrity.
UPDATE: Ukraine's intelligence chief says Russia is reinforcing the fortified city of Kherson to fight for it. Does Russia intend to fight for all of the west bank of the Dniepr River or just a bridgehead at Kherson to retain options for an offensive to Odessa? Or is reinforcing the city just to make it the last bridgehead to cover the final withdrawal to the east bank? Or are Russian troops just passing through and paused waiting for a crossing opportunity?
UPDATE: ISW assesses that while Russia is withdrawing from some parts of Kherson province, Russia is prepared to defend Kherson city. Also, Russia may only plan to blow the road on the top of the Kakhovka dam. And then there is this:
Kursk Oblast Govenor Roman Starovoit announced the completion of the construction of two reinforced defense lines on the border with Ukraine on October 23 — likely an act of security theater designed to target a domestic Russian audience since there is no danger whatsoever of a Ukrainian mechanized invasion of Russia.
Why would it be reassuring to suggest Ukraine can invade? Odd, no? Also:
Ukrainian forces continued targeting Russian force concentrations near the Zaporizhia Oblast front line on October 23–24 and struck a Russian force and equipment concentration in the vicinity of Enerhodar on October 22.
I mentioned it seems like Ukraine is striking more in this region lately. Will Ukraine shift its offensive efforts here?
UPDATE (Tuesday): The Russians are no longer just fighting Ukrainian Nazis. Or NATO. Or the West, in general. Now Russia is fighting Satanic forces in Ukraine. So there's that.
UPDATE (Wednesday): The war has been raging for 8 months. For all the attention to Putin's mobilization order, what did he do with the spring recruits? They could be trained and equipped by now, no? Or were they fed into the line over the last 8 months to replace losses at the front? I can't say I remember reading about that. But if they exist as new units, where are they?
UPDATE: Russia seems conflicted about their positions on the west bank of the Dnieper River in Kherson province. For a while it seemed clear that Russia was evacuating. Now it seems like Kherson city at least will be defended. Is there confusion in Russia's command? Do generals want to avoid losing troops isolated on the wrong side of the river while Putin wants to keep a bridgehead to eventually resume an offensive on Odessa? If there is confusion it might guarantee that Ukraine captures a lot of troops on the west bank if it ever fires up its offensive there.
UPDATE (Thursday): I read stories about Ukraine's Kherson offensive. I even read one that said Ukraine was surrounding Kherson from the west. What offensive action? I don't see it. Unless Ukraine has really clamped down on information about capturing territory the front has remained static. Why? Is Ukraine too weak to push the Russians back? If so, why? Are Russians more capable of fighting than they seem? What is going on?
UPDATE: What I hope is that Ukraine is trying to suck Russian forces across the Dniepr River where they can be cut off by blowing bridges and ferries. And then the Ukrainians strike south from Zaporizhzhya to advance on Melitopol. But I have no idea. I may expect too much.
UPDATE (Friday): Russia's "Wagner offensive" continues to batter its army against Ukrainian defenders on the Donetsk front, slowly grinding forward at high costs; Ukraine continues to slowly take ground north of that on the Luhansk front; and Ukraine continues to pound Russian supply lines and perhaps is taking some ground slowly on the Luhansk front.
Can either side mass sufficient power to make more real gains this year? Will somebody suffer a cracking of morale on a section of the front and see their army flee from such an offensive?
UPDATE: Oh?
Ukrainian forces have steadily recaptured territory on the west or right bank of the Dnipro. The front line is 30km (18 miles) away from the city, according to Ukrainian officials.
I don't think the front line west of the city has moved much in months. The only major advance was from the north and that has been static for several weeks.
UPDATE (Sunday): I thought the Russians pulled their fleet back to the eastern Black Sea:
Social media footage documented an unknown number of unmanned surface vehicles striking at least one Grigorovich-class frigate in Sevastopol on October 29.[1] Footage also showed smoke near the port in Sevastopol and what appeared to be Russian air defense in Sevastopol engaging air targets.[2"
Watch for confirmation.
Also from ISW, is Russia preparing to simulate an insurgency, anticipating Ukraine's liberation of the Kherson region on the west side of the Dnieper River?
Russia is likely expediting efforts to forcibly depopulate areas of Kherson Oblast along the Dnipro River and repopulate them with Russian soldiers, some out of uniform in violation of the law of armed conflict.
ISW suggests it is to make it look like Ukraine is shooting at civilians when in fact the targets are soldiers pretending to be civilians.
UPDATE: NYT: A combination of spotter drones for more accurate Western artillery and ammunition plus shortages of ammunition for Russia's mass fire-based artillery may have given Ukraine's artillery the advantage over Russia's artillery capabilities.
NOTE: ISW updates continue here.
