Russian politics is a tough business, Putin is the toughest of the bunch. He understands the limits of Western Power and its weaknesses. He will do just as he pleases and there is nothing the Western Powers can do that will stop him without bringing a terrible cost to their prestige....what there is left.
When you are known to be weak and vulnerable....and are....this is the kind of thing that happens.
US Military power has gone from one of being able to fight Two War's simultaneously.....to being unable to fight one by itself. That is a fact....and publicly admitted.
When the US Army announces it has exactly two Combat Ready Brigades....you think the Russians are not aware of that fact?
Military action from the USA is not a risk.
The UK Military is more a Home Guard these days and certainly not an Expeditionary Force anymore.
Economic Sanctions are not a risk....what happens if Russia cuts off the supply of Gas to Europe in retaliation for any Sanctions taken against them? The UK and European Economies cannot sustain any real harm for a number of reasons....and the US Economy surely cannot.
The only avenue left is the UN....and who sits on the Security Council with Veto Power?
As I see it....the only thing left is Public Hand Wringing... and lots of talk.
That is something the Welfare Man is very good at.