It’s putin’s wet dream, to break the “Atlanticist” alliance and with it, NATO; to reverse the outcome of the Cold War. I think the ramifications would be too complex to game out with any confidence, other than stating the obvious: the world order would become multipolar (as putin prefers), with power centers in the USA, Europe, China, probably India, probably Russia. I could see US foreign policy shifting from its focus in Europe to the Pacific and intensified efforts to thwart China (which faces a demographic calamity that threatens any long-term potential for hegemony).
In reality, the ties that bind Europe to America (& Canada, Australia, etc.) are more resilient than the damage caused by your trumps, orbans, farages, etc. Rational actors will prevail when the stakes are so high.