Scotland is too poor and too small to contribute to the EU without the backing of Big Sister England, Cousin Wales the Bank of England and the pound. The Crimea is huge with massive resources. There is no comparison.
All over the world, there is trouble and strife for different reasons, and a war or wars, somewhere, are brewing. And Britain has sold herself to the highest bidder and left us truly vulnerable.
Something like that. The UK (and other countries) have Treaty obligations, otherwise, Treaties are useless and any totalitarian leader can do what he likes and invade where he likes. That's why we had to defend Poland in 1939. The rumblings and diplomatic posturings going on at the moment are...
Well, Russia made a grab for Ukraine in about 1753. (Germany and Austria-Hungary made careers out of trying to squeeze Poland off the map.) The Crimean War of 1854 and the Charge of the Light Brigade was one of the outcomes.
And get into a position where he can hold the West to ransom by denying them access to the fuel Russia now provides them with. Utter stupidity on the part of the West to give Russia such an Ace card.