The war won't have happened if the US and some western countries have kept to their promise of not expanding NATO towards Russian borders. And moreover, both Ukraine and Russia are brothers, just in arms. Russia is simply trying to survive hostile NATO policies.
The war won't have happened if Russia didn't invade Ukraine.
Russia wouldn't have invaded Ukraine if the US hadn't gone back on its agreement to not expand Nato, and if they hadn't pushed Ukraine into harming their own people and some Russians as well.
Maybe in BADeckerville.
In the real world that "we won't expand NATO" promise is a fantasy, it doesn't exist. Just like the whole "tHeY aRe CoMiTtIng GeNocIdE!11!!" bullshit.
Unless you are speaking as a current resident of BADeckerville or some other make believe land, you are mistaken. The existence of a document describing what was discussed among non-heads of state during negotiations to establish NATO is not the same thing as what was actually agreed upon by the actual heads of state - which is well documented.
Don't believe me? Just ask Gorbachev:
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Russia Beyond Journalist: One of the key issues that has arisen in connection with the events in Ukraine is NATO expansion into the East. Do you get the feeling that your Western partners lied to you when they were developing their future plans in Eastern Europe? Why didn’t you insist that the promises made to you – particularly U.S. Secretary of State James Baker’s promise that NATO would not expand into the East – be legally encoded? I will quote Baker: “NATO will not move one inch further east.”
Mikhail Gorbachev: The topic of “NATO expansion” was not discussed at all, and it wasn’t brought up in those years. I say this with full responsibility. Not a singe Eastern European country raised the issue, not even after the Warsaw Pact ceased to exist in 1991. Western leaders didn’t bring it up, either.
Mikhail Gorbachev: The topic of “NATO expansion” was not discussed at all, and it wasn’t brought up in those years. I say this with full responsibility. Not a singe Eastern European country raised the issue, not even after the Warsaw Pact ceased to exist in 1991. Western leaders didn’t bring it up, either.
https://www.rbth.com/international/2014/10/16/mikhail_gorbachev_i_am_against_all_walls_40673.html
NATO has
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NATO is the mechanism for securing the U.S. presence in Europe. If NATO is liquidated, there will be no such mechanism in Europe. We understand that not only for the Soviet Union but for other European countries as well it is important to have guarantees that if the United States keeps its presence in Germany within the framework of NATO, not an inch of NATO’s present military jurisdiction will spread in an eastern direction.
Since then, there have been five rounds of NATO's eastward expansion. 
