The timing of this was purposeful with the Olympics in play and the American President in China. The Russian’s are acting very deliberately and they know that the US is weak now with elections pending the economy in mess. This shows you that perceived weakness will be taken advantage of and we are way late in responding to this.
The cost of Europe and the US's "talk" response will be more than we will ever directly know. How many former Soviet states will suddenly get a lot more cooperative with Russia? Will Ukraine decide that is must accommodate a Russian military presence permanently? What about the oil and gas rich 'stans who now will either have their access to the West cut off or will have to cater to Russia to make sure that their oil gets through? etc. etc.
While the Russkies are devils, they're seldom fools.