No russia is not weakened only because of western sanctions about its actions in Crimea. Russia has been on a decline for a while, since the collapse of the U.S.S.R. The only thing Russia has now that keeps it relevants is its natural resources(oil, gas reserves) and its remaining old arms industry left from the Soviet era. This makes Russia a country nobody can ignore since it has a large landmass,resources and old weapons relics from its soviet days. IIt is an important country still, but not as important as it thinks, This is mainly due to the fact that, the world today and tomorrow is mainly economic in nature. Countries with the largest economic influence,trade, market,technology, manufacturing, services, etc will be the ones to set world agendas and influence any new world order. In this regard Russia is still weak economically, and in future it might get even worst, not because Russia economy is in decline per say, but simply because other developing countries are growing at a faster rate than Russia, and are set to overtake it in future, read India, Brazil(which is already bigger than Russia ironically), Mexico, Indonesia etc are all set to surpass russia in the coming years/decades. In this regard Russia only has its military relic from the soviet empire to rely on if it wants to keep/maintain its influence.
This is one reason you see the U.S/west still regard China as more of a threat to its world hegemony than Russia(though we still condier Russia a major threat, but its mostly regional in east Europe not global like China), simply because China in the coming decade will be so much bigger economically that it wont be easy for the U.S/west to maintain our economic hegemonism/influence all over the world. So the 21st century battle will be fought mainly economically,Financially, cyber warfare, sanctions etc rather than militarily, especially among big powers like the U.S and China . Small countries might be involve militarily but it will be as proxies of big countries as we are now seeing in Ukraine/Syria.
As for your point of Russia not staying Neutral if China becomes more aggressive towards Vietnam(or if there is a war), Are you trying to say Russia will support Vietnam against China?
lol
I think you dont understand big power politics quite well. Russia has way more similar world views/interests with China. Their relationship is more deep than with little Vietnam. Russia wouldn't even take India's side in any conflict against China(and mind you India has way more influence and is way bigger than Vietnam), and you think they will take little vietnam side? Vietnam simply has no real importance to Russia like China does. Vietnam is simply too small to even count on russia world strategy against the west. I think Vietnam should be more realistic. I know your relationship with Russia has been on since the soviet period which you find difficult to change, but the world is different today, no country has friends or permanent allies just permanent interests. Rememebr China and Vietnam were once strong communist brothers/allies and China supported Vietnam Militarily and economically during th vietnam war(without which the U.S would have fully invaded the north long ago and won the war) but today is vietnam still friends/ally with China? not hey arent since their interests dont match anymore. So Vietnam shouldnt feel like it owes Russia anything, it should ally with the U.S who can provide much more support to it than hoping Russia will take it side against China.lol
There are only 2 options for Vietnam, it can either follow Philippines and Japan example and fully ally with the U.S which i think is the best option
or it should stop crying/whining about being bullied by China and negotiate a compromise with China on the SCS issue(which it will have to make compromises being a far smaller country).
I hope Vietnam makes the right Choice, they have suffered enough in the past(being bombed and destroyed during the vietnam war and subsequent border conflict/invasion from China, with their own invasion of cambodia as well), i dont want to see it suffer again by making wrong decisions in the future. Wishing Vietnam all the best.