This is not a "belief".
This is the reality of the world. Just as the USA gets to determine how other sovereign nations conduct themselves, witness Panama being invaded when they sold secrets to Cuba, if those sovereign nations are in the US sphere of influence, so does Russia get to determine how other sovereign nations conduct themselves, if they are in the Russian sphere of inluence.
And Ukraine conducted herself abominably, jumped into bed with hansum man America and then did a gangbang with Europe on top, when its boyfriend Russia was paying her energy bills. Cheating is an ugly betrayal, and Ukraine now pays the price.
No. This is neither belief nor reality. It is a choice.
One the West and free world must make. History, especially that of Russia and Vladimir Putin, has recorded the peril of allowing Putin to drag the world back to the gory glory days of slaughtering cultures and territorial conquest. Not viable with nukes.
How does the West have the ability to chose? Because of NATO's 50 trillion GDP combined with other freedom loving countries. Putin is peanuts.