Modern tanks are pretty capable cross-country, but they have a long supply tail. An Abrams tank (which, to be fair, is more of a gas-guzzler than average owing to its high weight and its cool-but-questionably-practical turbine engine) gets about half a mile to the gallon and has a nominal range of a bit under 300 miles, which overstates its operational range because warfare tends to involve a lot of waiting and a lot of local maneuvering.

Strategically, you can only move armor as fast as the trucks or railroad cars carrying fuel, food, and ammunition, and that means that roads, rails, and bridges remain important. (A bit less so if you're somewhere like Iraq, though, where you've got lots of open, hard-surfaced desert to work with.)

This is the situation where it could be useful to have a prediction market for "which country will be next invaded by Russia?". I don't have high confidence for my predictions here.

My guess is merely: within 10 years, Russia will invade another country, one they share a border with. But I'm not sure which one.

Finland seems like an interesting target: it is a EU member, but not a NATO member. NATO has weapons, EU has rationalizations why not doing anything is the wisest policy ever.

On the other hand, there are former Soviet Union countries where Russia can use the excuse "they belonged to us historically anyway, and there is our minority we have to protect". I don't know how important each of these factors is for Russia when deciding its next target.

1) Why should we let the Ukraine join NATO? It escalates us towards a war against Russia, and really if we wanted the Ukraine to join then the offer would have been made before the war started.

2) I'd guess that something with the complexity of a ballistic missile shield probably can't be kept secret. For instance, if you were going the 'star wars' route and sticking weapons in space, then the Russians are going to wonder what all these new satellites being launched are for. I suppose you could disguise them as spy satellites, but its still a clue that something's going on.

3) Isn't Russia exporting gas rather than oil? In which case it is being used for heating and power rather than transport.

Some "land wars in Asia" are successful. For example, Germany successfully conquered Russia in 1917. Even more relevantly, Poland ejected the Russians from large parts of the Ukraine in 1921. I think the saying gets its popularity from a very superficial reading of history. Yes, Napoleon and Hitler famously came a cropper, but there have been plenty of successes.

European militaries are extremely capable, for the most part - pound for pound, they're almost as good as the US. They just have a lot fewer pounds.

And historically, land wars in Asia haven't been a big deal. That's a Vietnam-era myth - WW2 involved a lot of Asian land warring, and that went pretty okay.

US does. European military isn't particularly large or capable.

http://www.globalfirepower.com/ says that the UK, France and Germany are the 5th-7th most powerful countries respectively. UK tanks are probably the most powerful in the world, based on the idea that whoever shoots first wins (at least when you're firing depleted uranium rounds that can punch straight through a tank), and the UK holds the record for longest distance tank-on-tank kill.

The US alone has over 8x the defence budget. The UK, France and Germany together have almost twice the defence budget.

Sigh. Do the words "land war in Asia" ring any bells?

Yes... this is because Asia is very big, and armies can freeze on the way to Moscow. But the Crimea isn't that big.