This is a little broad.....maybe if YOU picked the vehicle and the war we could extrapolate as to whether it would have mad a difference. For example if someone sent a tank back to the Thirty Years' War it would have made a profound impact. How would you judge which answer is correct? If someone chose the Apache helicopter and WWI, and someone else chose an AR-15 and the Thirty Years' War.

@DustinJackson Call it a Challenger II battle tank then. However, the point of this question is to evaluate which war it would have last made a difference in... any suggestions for narrowing down that?

I think we can answer this in terms of era/military technological levels rather than a specific war, but an example wouldn't hurt answers.

Is additional fuel and ammunition available, or should the standard payload be considered the only armament? In anything medieval and earlier, the only limiting factor is really fuel and ammo.

I think virtually anyone with a knowledge of our military could answer with any of a million different weapons that would have surely changed the tide of a war. This is either unintentionally too broad or an idea generation question.

@Twelfth Assume resupply once per week, using the same time machine you used to bring the tank there in the first place

@DustinJackson My first comment to you. This is no longer any weapon, it is one C2 tank.

If you landed it at a strategic place, it could well have made a difference even in WW II. Just think about landing it directly in front of Hitler and firing a single shot before anyone has time to react.

theres a game called civilization where it can happen of you having a tank while your enemies have units like musketman from the 18 century

@JorgeAldo - Civilization 3 had an odd occurrence where a spearman would successfully defeat tanks far too consistently...enough that it became a very common complaint. Type Civ3 spearm into google and it should auto complete to display a huge list of complaints with tanks falling to spearmen.

of course those spearmen are elite, they throw their spears in the tanks guns muzzle, when the tanks fire they explode

Technically speaking, an ICBM is a military vehicle. A single one of those could turn the tide of any past or current war or any war for the foreseeable future, considering that a large percentage of the world's countries are sufficiently small that they could be utterly destroyed by a single nuclear-armed ICBM.

@celtschk or land it just above Hitler and you needn't fire a shot...

@reirab: "considering that a large percentage of the world's countries are sufficiently small that they could be utterly destroyed by a single nuclear-armed ICBM." You definitely overestimate these.

@SF. I was including areas rendered unusable by radiation. Also, remember that a single ICBM can carry multiple nuclear-armed re-entry vehicles. While a single missile couldn't affect an entire country the size of the U.S., Russia, China, Australia, etc., it definitely could for countries the size of the Koreas, several of the smaller (or even mid-sized) European nations, etc.

@SF. Castle Bravo is a good example of quite how powerful those things can be. We never actually made any ICBMs that powerful, though, largely since it was deemed impractically powerful. Within 10 minutes, the mushroom cloud alone had reached a diameter of over 60 miles.

@reirab: Most MIRVs don't exceed 5MT; MIRVs usually go in sub-megaton sizes per warhead. Besides, hey, no moving goalposts please! An aircraft carrier is a military vehicle too, are you going to include a hundred airplanes and helicopters on board as "component"?

If the tank gets refueled every week then it has a very few shells. Even if no one can blow it up frankly it will run out of ammunition relatively quickly in a major battle, greatly limiting the harm it can do. if the war is low-tech enough, but if they are that low tech odds are the "THE METAL GOD OF DEATH IS POINTING HIS FIRE BOOM STICK AT US, SACRIFICE A GOAT TO IT THEN RUN" is probably the response your going to get from any military anyways. Militaries advanced enough to TRY to fight it are probably advanced enough that running right over infantry will leave you vulnerable to them

also, Just FYI, My Laptop still beats your Tank. You can prolong WW2, but I can help them build a nuke to blow you up. Just saying :)

@dsollen Just don't get that laptop in my range...

I would say every war before WWII. There is simply not enough ammunition to do much of anything, but the physiological effect of the hugely advanced technology would get you a victory in most other cases. As soon at those WWI soldiers saw it coming and saw bullet and mortar shell bounce off, you would of won.

Actually, a tank could be quite powerful in WW1 without fireing a shot. If it bulldozes a line between trenches and then blocks enemy fire it would make charges much safer. Not quite battle shaping by itself, but hey if after you finish raining death on everyone you can still be a major asset that's pretty good.