Let me address specific points in your post NewJak:
a) You said that I am forgetting Cain has the ability to take out an army.
Actually I agree with that. You stated that he can punch the ground and cause an earthquake. Well, I’ve never seen that in a comic but I am sure that he can do it (and if you say he has done it in a comic I believe you, since it is certainly within Cain’s defined power-set). The only thing here is that personally I do not see what REAL difference it would make once the ‘Cain army vs Confederate States’ situation takes over.
His battle-field effect (punching the ground and destroying an army) would simply be something similar to military technologies that were created around 5 decades ago.
Tactical nuclear battle-field weapons!
The Soviets had a system called ‘Frog,’ which was basically a rocket with a small tactical warhead. The United States had a similar rocket system called ‘Honest John,’ which could also carry a small nuclear warhead. Furthermore the US even had true artillery that could carry a small nuke and was supposed to be used to take out armies. Goodness, there were even nuclear landmines (designed by both sides) that were intended to take out entire armoured divisions. For example the US thought of placing nuke mines to take out possible Soviet tank advances through the Fulda gap into (then) West Germany, and the British had possibly the zaniest nuclear landmine idea (they didn’t know how to keep the mine warm enough for the components to work, so their idea was to fill the large landmine with LIVING chickens with the hope that their body heat would keep the thing functioning for long enough. Obviously that mine design was only useful for a shortwhile).
Anyways, my point is that in real warfare the ability to take out armies has been there for quite sometime (actually a small number of planes carrying some cluster bombs could do the job extremely well).
Once full war broke out Cain’s ability to take out armies would be totally negated ….he would be doing something that any modern army could also do. It wouldn’t have the demoralising effect you think it would have.
A good (real world) example is the Viet nam war. The US dropped so much ordinance there, some of it TRULY spectacular. Then they started doing the whole Agent Orange thing, wiping out entire swathes of forest. The Vietcong was getting killed en masse.
Result: Their will to fight got reinforced.
b) You said: So with that kind of power coupled with abilily. Cain could would take over armies simply through fear but along with his own strength he could conquer any nation. He could make a broadcast to every nation on Earth join him or perish. Once they launched their nukes and found out Cain couldn't die they would understand they don't have a chance. People fight back when they have hope. With Cain there is no hope eventually the nations of the world would realize they can't do anything.
This is the one point where I have to disagree with you completely. History has shown over and over again that ‘lack of hope’ can actually make a people fight harder and longer. After all, they have nothing left to lose and are not fighting simply out of principle.
An example of this was when the Nazis invaded Russia and quickly destroyed every resistance that the Soviets tried to put up. The Nazi war machine was simply too powerful for the Soviets. Then they went to Stalingrad and cut off supplies to that city (many Soviets died from starvation), bombed the city over and over again, and shelled it until the entire place was almost gone.
What happened? The people lost all hope, their own government couldn’t do anything to help them, many of their children had died, the only thing left of their lives were memories, and the besieging German army was within shouting distance!
What did those people do? They formed an even stronger resistance that ADAMANTLY refused to give up the city. Men fought, women fought (actually one of the snipers with the highest body count was a woman - Ludmilla Pavlichenko is credited with 309 dead Germans, each with a single shot). Actually talking about women, 800,000 plus Russian women fought in WW2 (and when I mean fought I mean real fighting …..70% of them fought in the front-lines).
Russia lost 30 million lives in WW2, but they still went on. In the end the Russian winter and the determination of the Russian people stopped Hitler’s plans in their tracks, and the Nazis never recovered from that.
Another example (which by the way has been brought into comics) is the battle between the Spartans and the Persians at Thermopylae. In comics it is shown in ‘300’ (of which a movie was made in 1962, and another one is coming out this March).
The Spartans faced overwhelming odds – suicidal odds – and the Persians (and overwhelming army of them) simply couldn’t defeat them hand to hand. The Spartans (in the real event) were finally killed by a hail of arrows. That battle became a rallying call for the Greek city-states by the way.
Anyways, my point is that history has shown over and over again that the most dangerous adversary is one without hope!
A person without hope of winning (be if a Vietcong guerrilla against the mighty US army, some goat-herder turned Mujahadeen in Afghanistan fighting against the Soviet army, a poor Russian woman picking up an old rusted rifle to face off against the Nazi machine, or 300 doomed-to-die Spartans facing off against thousands of Persians) has nothing to look forward to. Consequently they have nothing to fear. Nothing to lose.
By the way in the ‘real world’ this is one of the criticisms that has been brought up against some military strategies. For example the Western mindset always finds it so weird that someone can be a suicide bomber. Today it is the Islamic terrorist, and in WW2 it was the Japanese Kamikaze.
It is always so alien to Western minds why someone would do that, yet it is a cultural thing.
For example take the Nazis invading Russia. The Soviets never gave up, and every loss they encountered actually made them fight harder. To the Germans that did not make sense (actually when the Russians, and the US, started moving into Nazi Germany the Germans started to surrender).
It is the culture. What was ‘logical’ to the Germans was unacceptable (actually foreign) to the Russians.
Just because Cain can cause fear and doom doesn’t mean the entire world would fold before him. It could actually backfire.
c) Basically the first 6 major cities Cain destroyed without being stopped people would relaize they've lost.
Napoleon actually thought the same when he invaded Russia.
When he was retreating back to France, his army broken and is vision destroyed, he realized his mistake.
Entire books have been written on that.
Another example is America.
While many people assume Americans are soft (when things are peaceful they SEEM to be) the moment things hit the fan the people come together and their wills turn to steel. Take Pearl Harbor for example ….what the Japanese thought would break American will actually turned them into something that would destroy the Japanese empire a few short years later.
Imagine what would happen if New York was destroyed, Los Angeles, Chicago, Dallas, Washington DC, and Seattle (you said 6 major cities ….I’ve made it 6 major cities in one country instead of 6 cities around the world, thus I have actually concentrated things).
What do you think the reaction of the people would be?
Would they simply lay down arms and submit to Cain?
Well, I am sure there are millions of soft-willed people who would do exactly that. But there would be millions who would simply find the destruction of those cities such a blow that they would NEVER give up, even if it meant their deaths.
d) Plus with planes and stuff like that Cain can literally be any place in the wolrd in a matter of hours.
Well, not necessarily in a matter of hours. For example certain Special Forces teams in the US and Britain are rapid-reaction teams, and are supposed to be anywhere in the world in the shortest time possible.
Their target is 72 hours. (Remember this thread was looking at a real-world scenario, thus in this world there is no X-Men Blackbird or similar to take Cain around the world in 2 hours).
Why is it that long when you can be in Australia in 48 hours?
Well, because they know in a war situation refuelling is an issue and they have to fly around places that in peacetime they could normally fly through. Thus their ‘shortest time’ is much longer (yes, I know Cain cannot be killed, but if a MANPAN SAM hits his plane and it crashes he has to walk or wait until he is rescued. BTW, compare and contrast this with a Green Lantern type or a Superman type).
Anyways, even if we take 48 hours (we should be using 72) one should realize that A LOT can happen within that time.
And what if 5 separate insurgencies are breaking out simultaneously?
Let’s say there is an outbreak in Argentina, in New Zealand, in Taiwan, in Senegal, and in several Canadian cities? What does Cain do? Jet hop from plane to plane putting out fires?
He could send his armies, but then it would be his army versus the ‘Confederate’ armies (or for that matter small bands of guerrillas that could never be stomped out).
What does he do?
Take plane after plane racking up air-miles?
It would be totally inefficient.
Comparison:
Cain would find it very easy to take over a region.
However he would find it very difficult to stop the rise of an insurgent movement, and he would find it impossible to stomp it out all over the world.
In comparison to Superman (or GL, and a Mjolnir-using Thor) Cain’s abilities to take over the world become a mere shadow.
Superman could literally take over the world. And keep it.
Cain would be forever putting out insurgencies.
That is the difference.