Thread by @BrynnTannehill

Multiple sources that I consider both diligent and conservative in their assessments (including DefMon3 and ISW) are showing that Ukraine has reached the main trench line outside of Verbove. This deserves some discussion. 1/n

They have made it past the initial anti-tank ditches and dragon's teeth. Getting past this line in force would represent a significant tactical gain, as Russia reportedly front loaded it's defenses at the first of the "Surovikin Lines". 2/n .theguardian.com/world/2023/sep…

"Brig Gen Oleksandr Tarnavskiy estimated Russia had devoted 60% of its time and resources into building the first defensive line and only 20% each into the second and third lines because Moscow had not expected Ukrainian forces to get through." 3/n

Take this with a (small) grain of salt, as Ukraine is keen to frame information in ways that keeps western aid flowing. But, based on the Russian reactions to Ukrainian advances around Robotyne, this seems more than plausible. 4/n

Russia pulled the 76th Guards Air Assault Division from the Eastern Front around Klischiivka to reinforce the area around Robotyne and Verbove. These are among the best, and most well equiped troops they have. 5/n forbes.com/sites/davidaxe…

The 76th has taken significant casualties throughout the war, and also perpetrated the Bucha massacres. It has also seen months of fighting around Bakhmut. But, it's about the best RU has left. It's one of the few capable of offensive actions besides meat-wave zerg-rush 6/n

The fact that Russia would commit one of their few units left that are capable of real counter-attacks that don't involve human waves of prisoners, press-ganged foreigners, and mobiks says a lot: the 76th WILL lose capability over time that they cannot reconstitute quickly. 7/n

Despite the headline in the Forbes article, it is unclear how much reserve Russia has, and where. Because there is near troop parity in country, RU can pull troops from one area to defend another as they did with the 76th.

Ukraine, for it's part, is throwing theirs too. 8/n

We saw the first loss of a UK supplied Challenger 2 tank yesterday near Verbove. (The crew reportedly survived: western equipment is very good at protecting their crews, unlike the ex-Soviet stuff participating in turret-toss competitions) 9/n

https://twitter.com/i/status/1698457342071734534

Ukraine has been committing both experienced units, and newly formed, western equipped ones to the fight at this point. They have also been allocating much of their precious artillery resources. UKR artillery has parity or better in the area. 10/n

https://twitter.com/UAWeapons/status/1698955326496592140

Now that Ukraine is inside the trench it becomes a particularly bloody affair clearing it one bend at a time. The map below shows a zoomed in guess at the situation. But, mines become less of a factor once you've cleared a path. TO the trench. 11/n

However, while Ukraine once enjoyed superiority in small drones for reconnaissance, that is no longer the case as Russia has mobilized significant resources to acquiring fleets of them. These are crucial to SA when fighting to take or hold trenches. 12/n

So, a Map from Brady Africk helps show why everyone is throwing the kitchen sink at this one spot: it's only about 5.5 miles from this spot, to the LAST fixed set of lines in the Russian defense. And it is likely that the defenses were front loaded. 13/n

Russia put the most effort into building up the first line, and less and less from there. We know that the 3rd through 5th aren't continuously manned: they're fall back positions. Which brings up the big question: Mines. 14/n

Based on video evidence the mine fields at the first lines are incredibly dense: so much so that US Army doctrine would consider this density to be impassible (blocked) for planning purposes. RU has the ability to re-seed mine fields with artillery 15/n

https://twitter.com/BrynnTannehill/status/1698131957878608353

However, Russia does not have an infinite amount of mines. They can re-seed areas with mines on the fly, but not to this density level quickly. If Ukraine manages to clear the trenches around Verbove, it is possible that things get easier going forward. 16/n

Which brings me to how would I consider the offensive to be a success, and that really comes down to two things that need to happen before culmination:

1. Have they made it to the last line?

2. Do they have enough left to prevent re-entrenchment?

17/n

The goal is to get to some point where Ukraine finds an "open backfield, and Russia doesn't have more fixed fortifications and ultra-dense minefields to fall back on. Once UKR reaches a point like Romanivske, it almost doesn't matter where they choose to hit next. 18/n

The mid-term goal isn't to retake Tokmak or Melitopol: it is to sever Russian GLOCs between Rostov and Kherson / Zaphorizhia / Crimea. If UKR gets through the fixed fortifications, they have more options to continue south, hitting wherever RU is weakest along the line. 19/n

As long as UKR is advancing towards the highway between Berdyansk and Melitopol, they're making strategic gains, particularly as GLSDB comes on line and holds more airfields, ports, and rail lines at risk. 20/n washingtonpost.com/national-secur…

The second part of this is that Ukraine needs to have enough ammunition, vehicles, people, fuel, etc... left to follow up on gains. This has been part of the the debate between Washington and Kyiv: Ukraine has been loss averse since the initial assault. 21/n

Every unit / vehicle / 155mm shell that you use penetrating the lines is one you don't have for the break out attempt. The offensive is a failure if Ukraine gets past the last line, culminates, and then spends the winter watching RU build NEW lines in front of them. 22/n

The Ukrainian dilemma is how much to spend getting through the lines, and how much to hold back so they can exploit a potential break through. Both are necessary but not sufficient conditions: they must do both and plan for such. 23/n

In summary: I believe we are seeing the most crucial moment of the offensive right now. Russia has proved competent at falling back on defense. However, as UKR advances into unprepared territory the threat of mines decreases, reducing the worst barrier. 24/n

From this, we can infer how to measure "success" for either side. For Ukraine, I would say that a successful conclusion is very difficult, but certainly not impossible either. 25/n