>>From Russian perspective:

I'd add not wanting a successful, prosperous democracy of Russian-speakers, with many connections to people in the RF to demonstrate that it's possible to NOT have an authoritarian style government.

Also, by 'Western oil/gas interests' you mean the majors? Here in North America, they haven't been able to compete in the shale oil/gas 'scrum' - and it seems that the discoveries under Ukraine were exactly that, not the 'classic' deposits the majors would be most capable of exploiting.

All that said, you mention China invading Taiwan. I don't see that happening, now that China has seen how difficult invading a resisting country is - and considered what would happen to their economy if the same sanctions were applied to them. For that matter, all the US has to do is announce that they are no longer protecting blue water international trade to/from China for a potentially economy-destroying event. China has a navy, but those ships do not have the 'legs' to escort global shipments (or even oil tankers going past India).

I don't think the US would do that, but if China was in process of invading Taiwan.

Not an expert at this, just someone who's read a lot of history, understands how geography affects nations' capabilities - and is trying to figure this stuff out.