Wars are won (and lost) as a result of supply chain logistics.

One of the most important elements of the war machine is a well-fed and well-equipped soldier. As such, most armies have dedicated logistics divisions to ensure supplies, weapons, and machinery get to where they are needed on time.

Consequently, supply chain interdiction or disruption is a powerful weapon of war. To interfere with your enemy's logistical operations is to reduce the overall effectiveness of their combatants and thus their strategy.

Modern-day Russia was not prepared for this war to last as long as it has, their commanding officers have little regard for their soldiers, and they've historically had poor logistics to begin with.

This makes it easy to disrupt their supply chains, if they were even set up in the first place. Add this to tribalist infighting and a general lack of cohesion and you end up with people going hungry.

It is really hard. Incredibly hard.

Part of the reason why the USA has such a dominant military is because it has built incredibly long and sturdy supply chains that can move soldiers and materiel around the world quickly to soldiers.

First, you need to get this to the front, which usually requires a supply chain, reserves, and a manufacturing base to replenish reserves. Russia's economy is ok, but this is the first war in a generation and the Russian economy is showing obvious cracks in being able to supply soldiers. You also have Ukraine getting its supplies from the best logistics force in the world and its economic allies.

Second, you need to actually deploy the resources to the front. That usually requires competent military logistics being able to move these supplies. If your logistics people are corrupt or incompetent, that may not happen to the volumes needed.

So, yeah, there appears to be logistics problems with the Russian military.

You might want to read about tooth to tail ratio on Wikipedia

https://en.wikipedia.org/wiki/Tooth-to-tail_ratio

In a sense, war is mostly logistics. It doesn't matter how strong your unit is, how clever you tactics are, or brilliant your strategy is. None of those things matter if the unit is not where they need to be, with the supplies to be effective.

Most countries have limited ability to project military force outside their country because the logistics become so hard to support. Russian military relies heavily on rail transport, which doesn't extend into Ukraine anymore, and trucks what it can't rail...but the supply depots need to be hundreds of km behind the line because of long range precision missile strikes. With long supply chains supported to heavily stretched trucking, guys at the front won't get everything they want.

(Not a military)

Cutting the supply lines is one of the most classic military strategy. In most armies there is way more soldiers involved in logistic and support than soldier actually fighting. If you want to get rid of the soldier fighting on the front-line you can send other soldier fighting against them, but they are trained and ready to fight or you can just cut the supply lines by destroying bridge and bombing supply truck/trains. During Napoleon's Russian campaign (people will start to believe I am obsessed with Napoleon) russia did burn the crop before withdrawing, and it's how once they reached Moscow the soldier had no food left and Napoleon's great army died from starvation while retreating under Russian winter

oh, and supply logistics were the reason the Romans built Roman roads, the reason the Germans built the Audubon, and the reason the United States built the interstates. it's a big deal

I'd bet everything in my pockets that there's some cyber-shenanigans going on as well. Requisition orders being dropped from their systems, or changed to something they can't use. Deliveries sent to a unit's previous location.

I have no real idea, only suppositions :

(I'm not treating Ukraine as the enemy, this is a full supposition).

The real hard part is costs and time. If the soldiers pushed the front lines, and there is no risk of enemy attacks behind the line, there can be multiple things in the way :

The terrain may not always be good for fast travel. With difficult terrains or mud and water.

And because front lines aren't perfect, there is always the risk of enemy attack behind, destroying supplies.

Now why exactly Russia did not send supplies to their soldiers, no real idea. They only know what they chose to do.

Ukraine is huge, giant. Going up to the front lines takes time and money. And well I very much guess that Russia just sent soldiers without care, maybe even now they doing that. They underestimated Ukrakne's defenses and the support they get from other countries.

Well, when you remember that a) Russia doesn't give a shit about its soldiers and b) Russia doesn't have a ton in the way of functioning logistics, it makes sense that the basic necessities are not being provided.

The Roman soldiers occupying Britain ate 33 tons of grain every day. I believe that Guadalcanal, because of the rivalry between the Japanese Army and Navy, they let 22,000 Army personnel starve to death before evacuating them. just didn't give a shit

Honestly? They have limited resources, so they have to prioritize the most important supplies. While you'd think keeping your soldiers in good shape is important, it may be less important than making sure the artillery units are getting their regular shipments of shells, stuff like that.

Especially if those "soldiers" are just some cannon fodder you recruited from a prison and sent to the front with no training. They probably won't live long, and you're not expecting them to, so it becomes a waste to spend resources maintaining them.

Also, there might be some corruption at play. Rather than explain that myself, I'll let Perun field it:

https://youtu.be/i9i47sgi-V4?si=nym2bddLZ1BW6zmL

This is part of how a much smaller army can defeat a larger invading force. The locals have all their supplies. The invading force has to bring everything with them.

This article contains a few words on the subject of logistics by some people whose names you might recognize.

Saw some research for the US military for deployable microbe fermentation "food factories" think it was like a humvee with a big storage tank on back. Bet it is bland as could be but food is food.

Would you want to drive a truck full of food into an active war zone to sell it to soldiers who have invaded your country and probably have no money anyway? Sounds like a good way to get yourself murdered.

"Bring war material with you from home, but forage on the enemy. Thus the army will have food enough for its needs."

-- Sun Tzu "Art Of War"

Short answer.

Harder than you think.

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