The war in Ukraine is only the latest but most obvious demonstration that the 'rules based order' no longer exists (https://archive.md/CMJWA):

Over the past several decades, the United States has continually placed Moscow in a position either to accept the fait accompli of NATO expansion at the expense of Russian security interests, or to escalate with force and suffer the consequences of increased economic and political ostracization. This disincentive to avoid escalation has been effectively removed. Explicating the altered state of international relations is not cheerleading for the Russian position — although it may be treated as such by those who disingenuously present any realistic assessment of the situation as “appeasement” — but rather illustrating how Moscow has insulated itself from Western ostracization, thus changing the entire balance of power in not only Europe, but the world.

Now, it is Russia that has the West on the horns of a dilemma: It can either watch the Kremlin achieve its strategic objectives, guaranteed in a one-sided negotiated settlement or through the continued attrition of Ukrainian forces, or it can escalate with force. Putin’s statement regarding nuclear weapons was not mere rhetoric—it was the Russian president defining the limits of the current conflict from a position of authority.

Anything short of total Ukrainian victory is therefore an implicit admission that the “rules-based” economic and political order has been irreversibly altered.