Analysis - West struggles as Russia moves to dominate old USSR

LONDON (Reuters) - NATO says tens of thousands of Russian troops are massed on the border with Ukraine for a potential invasion, yet Western states still lack a strategy to stop Moscow from intervening in its former Soviet neighbours.

With military action to protect non-NATO states effectively ruled out, current and former officials say sanctions and isolation provide the best - and perhaps only - way to pressure Moscow. Ramping up the pressure on the rich and powerful around President Vladimir Putin, they say, might in time push him towards a much more conciliatory approach.