> I'd argue that the "rules-based world order" as most people perceive it never really existed. Some will say that it existed for a brief moment in the 90s-2000s. Back then, most countries played nice with the international treaties even if there were no penalties for noncompliance

The utter disrespect for the CFE treaty during that period is exactly what got us the Ukraine war right now.

No, Putin's decision to launch the full-scale invasion in 2022 is what "got us" the war in Ukraine right now.

None of his claimed grievances in regard to the CFE Treaty amount to casus belli, by any rational metric. And they certainly weren't the core of what ultimately moved him to make that decision. They were just another part of his giant smokescreen, basically.

As his Deputy Foreign Minister put the matter, quite succinctly:

   Bondarev also recalled that Russian Deputy Foreign Minister Sergei Ryabkov screamed at US officials, including First Deputy Secretary of State Wendy Sherman, stating that ”[Russia] needs Ukraine” and that Russia will not ”go anywhere without Ukraine” during a dinner amidst the bilateral US-Russian strategic stability talks in Geneva on January 10, 2022.[67] Bondarev added that Rybakov vulgarly demanded that the US delegation ”get out with [their] belongings [to the 1997 borders]” as US officials called for negotiations.