> populace in a perpetual state of starvation and poverty, with the entire world in disrepair

This is quite different from my experience. In most of my Civ II games, I produce hordes of engineers, which I use to terraform the hell out of the planet--getting railroads everywhere, irrigation and farmland on all plains and grassland, mining on all hills, turning mountains into hills and swamp and jungle into forest, and eventually turning plains and forest into grassland and hills. (Only terrain with special resources doesn't get leveled like this.) I'd probably have 30-80 engineers at some point, depending on how big the game was. Anyway, with this cleanup crew, even if the ice caps melted or whatever the exact event is (which I think changes maybe about 1 out of every 10 squares), all of the new swamp or whatever wouldn't last more than a couple of turns.

Also, what causes the global warming events is mainly pollution: terrain squares containing pollution. That takes two engineer-turns to clean up per square. I would probably be able to nuke two cities and clean up all the pollution and rebuild the terrain (a nuke generally damages and pollutes the 8 squares around its target) in one turn. Srsly, why does he have any non-terraformed squares at all, let alone pollution?

The obvious--and probably only--answer would be "war -> engineers keep getting killed -> can't maintain and use such a cleanup crew". But even then... SDI Defense defends against missile attacks within three squares of a city, I believe. He mentions spies planting nuclear devices in cities. However, you could simply put units in the 8 squares around the city you want to protect [generally try to do this with all your cities, starting somewhere and expanding outward]. A unit by itself can be bribed by an enemy spy (unless you're a Democracy--oh man), but two or more units stacked are invulnerable to spies, even if those units are not combat capable (spies, for example). Then your only problem might be enemy conventional arms. Assuming this is a problem: Use your engineers, build fortresses in each of those 8 squares, and put veteran mechanized infantry there (6 base defense x 2 from fortress). Now you'll have equal odds against the most powerful ground unit, the veteran howitzer (base attack 12) (computers tend to use tanks, though, which have 10 attack). The last problem is stealth bombers, air units with 14 attack; but I think that if you have (stealth) fighters in the city, they will "scramble" to defend against bombers even in neighboring squares. And if not, then you can still at least retaliate next turn and kill the bombers, and not fall behind in a war of attrition (assuming they don't take the city that turn).

Oh, cheapo strategy as well: Have a (stealth) bomber end its turn in a ground square. No enemy ground units--or sea, or bombers or missiles, for that matter--will be able to attack that square. They will only be able to attack with (stealth) fighters, which have 8 attack; if you also have serious ground defense units in that square [or on a sea square, have AEGIS cruisers, with 8 defense x 2 vs air], and if that square also is foresty/swampy or hilly, or has a fortress like I've been saying you should make, then that square is basically impregnable without much attrition on the enemy's part.

Anyway: defend yourself; make your cities prosperous; accumulate capital (engineers are capital, and so are thoroughly improved cities surrounded by thoroughly terraformed terrain), out-produce your enemy, and don't lose the fruits of your production faster than they do. Eventually you should have a large surplus that you can spend on advancing in their direction. If there is a large no-man's-land between your cities and theirs, you should build little cities in this no-man's-land so you can put SDI Defenses inside them and extend your absolutely-defended area outward (rather like the Zerg creep). If nuking really is a problem, then you might just keep building cities within 3 squares of each other--or 2 squares so that you can put out SDI-guarded unit stacks to block spies. If the crowding bothers you, you can force intermediate cities to disband by buying engineers and stuff.

Eventually you should have almost a direct railroad connection to them, and at the front, fortresses on hills (or at least forest) within 3 squares of an SDI-Defended city, full of mechanized infantry that serve as "rocks for them to crash the waves of their attack against". They'll waste resources on trying to kill your units, and you should be mostly able to do what you like. Then either stack up a bunch of howitzers and kill all their defenses (at least in that city, possibly in others) in one turn, or, if you like, use spies to plant nukes and then capture the cities. When you take a city... If you expect them to nuke you and retake it, then, hmm, I dunno; can they really produce nukes and military units that quickly for long? If they have SDI Defenses, try to take the city with them intact (bribing the city is good if possible); if they don't, then I suppose it doesn't hurt to just nuke them. Or ignore them and keep on with the Zerg creep, perhaps treating "capturing their city" and "building a city in that location" as equivalent.

> democracy

Speaking of which, in Civ II, democracy has the following bad things when it comes to war: a) every unit costs a production shield to support (in monarchy and communism, this is "every unit after the first 3", and in fundamentalism, "every unit after the first 10"); b) as mentioned, your Senate will probably stop you from declaring war or refusing cease fires or peace treaties; and c) every military unit that ends its turn not in a city, or in a fortress within 3 squares of a city, causes 2 unhappiness in its home city that turn. Thus, a democracy is slightly worse off support-wise for a defensive war, and is significantly worse off for an offensive war. (But note that my above strategy can be done without causing any unhappiness at all.)

Democracy is the best government in Civ II for production and prosperity. I believe you get an extra trade unit on every square that produces trade; this translates to large amounts of science research and/or cash. Some of it must be spent on luxuries to prevent civil disorder, but it's usually still a large net benefit.

Btw, one annoying thing when nevertheless conducting an offensive war as a democracy: If you take a city, then enemy partisan units appear around the city, and when your active unit next encounters an enemy unit, they will talk to you, and they will offer a cease fire, and you will be forced to accept it, even if you wanted to continue attacking and maybe take some more cities. This problem can be somewhat mitigated by delaying the capture of a city until you've done all the other attacking you want to do that turn; also, if you are in a position to do a thing like this, you can:

Destroy all defending units in two or more cities. Before capturing a city, surround it--at least put units in the 8 adjacent squares, and ideally units in the full "city radius" of 20 squares. Then, when you take the city, no enemy partisan units will appear, and you will not be forced to listen to the enemy. You can then move up to another empty city and capture that as well (no enemy units, no contact with the enemy); if you have a bunch of maneuverable units (like spies or mech. inf.) and there are roads and mostly railroads everywhere, then you can even use the same 20 units for several enemy cities if you like. Of course, if you can do this, you probably won't have difficulty winning the game in any case.