system
Given the following post, respond as if you're commenting on Reddit:
human
[Walking Dead] How did the US military lose to a slow walking zombies?
gpt
Zombies don't have to fight the military- soldiers have to fight during a zombie apocalypse.

At the start, soldiers are probably well-armed and high on resources. The first zombies are probably dealt with by police- they shoot a crazy person in the head, and the soldiers don't even hear about it beyond rumours because... well, they're military soldiers, not domestic peacekeepers.

And then all of a sudden it escalates- SWAT's been overran, people are dying, and these soldiers are being sent in to fire guns and shells into unarmed civilians their own cities. Perhaps there's argument within the chain of command. Perhaps some soldiers still think there's a cure. Or perhaps some men can't psychologically cope with shooting people who by all rights they should never have had to shoot at. Either way, the attack is carried out, the day is won, but morale suffers for it.

Then things escalate again in the same area. They missed some, and the last failure- as well as similar happenings all over the country- left the police in too poor a state to cope effectively. The military returns, and this time they clear it out room by room, bringing supplies and rescue to beleaguered civilians and having to fight in close, bloody situations where the only difference between an enemy combatant capable of transmitting a lethal bioweapon and a child running towards you for safety is whether the crazed look in their eyes is fear or rage.

And while this is going on, new centres of escalation are breaking out. The military is stretched thin, and more costly strategies are invested to get breathing room- bombings, heavy weaponry. But this isn't an enemy country, and every bomb dropped, every tank ploughing through a field is damaging American resources, American supply lines, and both of them are what the military desperately needs given the initial resource-costly tactics and their duty to support their civilians. As civilians are killed and cluster together for safety, manufactories of all kinds begin to go dark- putting a time limit on how long the military has left to fight effectively.

The continuing increase in zombie concentration soon begins to fracture what supply lines are still available on its own. Roads going into town swarm with zombies when supply transport vehicles approach, stopping or redirecting some vehicles, damaging others, and often forcing those same resources to be spent on repelling the zombie trail the supply gathered. Overseas shipments are unable to make land as the noise and human presence (first dockworkers, later scavengers) of docks leave large groups of zombies ready and in position if a ship happens to come in. And all the while, resources are used up- on zombies, on enforcing martial law, and on providing aid to the country's citizens.

All this time, morale is steadily dropping. This shouldn't even *be* a war- it's a job for hospitals and police, not the *United States armed forces*. It's practically unthinkable that a disease- not even a bioweapon, a normal, bog-standard *disease*- is bringing the country to its knees. And yet soldiers are going in and shooting people, *American* people, people who they might be able to cure- and a lot of the time it's not even the infected they're fighting, they're fighting with people who have lost faith in the army's ability to protect them, who see the people who once protected them as resource hogs and bullies.

And eventually, under all this weight, something snaps- not frequently, not soon, and- initially- not far up the scale. It's small-scale, first. Perhaps a group of soldiers misses one zombie, and isn't willing to fire on their own comrade until the situation is already beyond their ability to control. Perhaps the psychological trauma of mistaken shots and firing on infected civilians leads to a localised breakdown in the chain of command. Perhaps a supply truck refuses to travel a route that's too risky for their survival. 

But the mistakes get larger, the cracks begin to propagate. The suppliers demand roads get secured, and they spend too much ammo trying to clear every stretch of road of zombies. A military base receives too many refugees, or what they think will be spare supplies are given out, and food stocks begin to run low. Civilians are drawn together to be protected, but a dead girl gets up again and the camp goes into chaos before things get under control. Stress runs high, and resources run low.

Then, finally, something breaks. A riot breaks out, ammo runs low enough for a desperate all-hands-on-deck excursion to resupply, the supply truck brings just a few more zombies than the soldiers can handle, a bridge breaks- and bases, bases that have never, *ever* lost a battle against the walkers, meet a population of zombies they aren't equipped to handle. Maybe they don't have the fuel to transport their soldiers and supplies in safety, maybe they don't have the food to sustain their stamina, maybe they don't have the guns to kill without losses. And just like that, a base has fallen.

As the process repeats itself, the higher governing structures are left relying entirely on goodwill- no promise of supplies, of effective strategies, of everything a soldier needs to survive; just a simple 'you have your duty' and nothing else. And, inevitably, people begin to leave- some soldiers disperse to find food or protect people, some establish their own fiefdoms out of duty to the locals or the need to get things under control again now that the government is unable to handle it. Some people remain, of course, but without the suppies or the command structure the military is a hollow shell of what it once was- more a well-trained militia or roaming warriors united by honour and duty than the sword of the United States.

The US Military has fallen. Not to zombies, no- but psychological stress, growing isolation and a desperate need for any resource that's available will bring a military to its knees in as drawn-out a process just as easily as it happens to an individual. 

They could gun down zombies in their hundreds, certainly- but War, Plague, Famine and Death are infinitely more insidious, and a lot harder to shoot in the head.