How many troops would it take to subdue a planet?

[Monroe]

This is a common theme in many Sci-Fi universes. The evil empire landing a garison or two (which we do have canon numbers for). The God Emperor sends a chapter of Space Marines. The Jem'Hadar plan to capture Earth.

Often in Sci-Fi I think numbers are horrible underestimated. Corruscant for example some sources say only hold 10 billion people when it easily holds arond 10 trillion.

Let's say that an alien force arrives to conqueror Earth how many troops do you think they would need? Would the Empire's Star Destroyer garison be enough when 300k soldiers can't keep peace in Iraq? Would they have to rely on mass genocide and turn coats?

[Sionnach Glic]

For a planet of around 6 billion, I'd say you'd need around one billion to keep a tight hold on the planet.
That's why I like 40K; armies numbering in the billions are common. 8)

[stitch626]

Well... in the original series, the Enterprise could stun large groups of people at once. With several ships doing this, it would not take long to subdue millions of people, even with a ground force of a few hundred. People wake up, stun 'em again.
Do this until you can hook up mind control units, and you have a huge new army.
However, just ground troops... I have no idea.

[Captain Seafort]

It depends on what you mean by "subdue". If you're talking about seizing the planet in conventional warfare, then a few tens of millions should suffice, possibly lower depending on the sort of firepower you're willing to employ.

If you mean holding the planet against a determined insurgency, such is being fought in Iraq, then the manpower requirements are much higher. In the early 70s it was estimated that fifty battalions would be required to hold Northern Ireland against a concerted insurgency - about 40-50 thousand men to control a population of a little over 1.5 million. This works out to about one soldier for every 30-40 civilians. For a planet of six billion individuals, this equates to 150-200 million men.

[Monroe]

That's an interestesting equation Seafront. Really makes the wars in Warhammer really massive undertakings. I agree with Rochey Warhammer does numbers right usually from what I've seen. I guess thats why the Empire in Star Wars kills so many people, its a lot more cost effective

[Jabber Swarky]

Well... in the original series, the Enterprise could stun large groups of people at once. With several ships doing this, it would not take long to subdue millions of people, even with a ground force of a few hundred. People wake up, stun 'em again.
Do this until you can hook up mind control units, and you have a huge new army.
However, just ground troops... I have no idea.

Wouldnt that be, well.. Useless? If everyones stunned for evermore, why not just kill them? Its not like theyre doing anything useful or helpful while drooling into the carpet.

Unless, you know, you just wanna keep em down long enough to steal their stuff, and then leave them to retalliate (Um, ok...)

[Sionnach Glic]

I think you replied to the wrong post. Seafort was talking about conventional warfare, as in people getting killed.

[Captain Seafort]

There's also the possibility of shielding to prevent such an attack - such as the Hoth theatre shield that required Blizzard Force to mount their ground offensive in ESB. Indeed, even Trek has demonstrated such devices in "Whom Gods Destroy", although in that case it was inferior to the firepower of the E-nil's phasers at full power.

[stitch626]

I thought we were refering to a more primitive planet, such as modern Earth. My mistake. Ok so ship phasers on stun would not always work.

[Captain Seafort]

Even against modern Earth the effectiveness of such tactics would be limited. The beam did no observable physical damage, which means it would be blocked even by typical buildings - you'd have to send troops down to clear cities the same way we do today.

Of course the alternative would be to bombard the offending city into dust, but this would be a bad idea. Firstly, your objective is to capture the planet and its resources, not lay waste to it. Secondly, killing large numbers of people tends to annoy their friends and you don't want to have to fight a full-blow counterinsurgency campaign - it's expensive and time-consuming, and defeats the object of capturing the planet for economic gain.

[stitch626]

Good point. Guess my idea would only realisticly work on very primitive societies.

[Captain Seafort]

Good point. Guess my idea would only realisticly work on very primitive societies.

It would be great for crowd control, and against troops both in the open and in exposed trench networks, so your opponent's mobility would be restricted. It just wouldn't allow a bloodless victory.

[stitch626]

OK. So how would we get a bloodless victory?

[Sionnach Glic]

My only suggestion for that would be to pump large quantities of gas into the cities.

[stitch626]

Hmmm... an idea