WHAT IF UKRAINE DOES NOT WIN?

Win is a difficult to quantify concept here. It is unlikely that Russia will win by taking the entire country, vanishingly unlikely. Even in a war of attrition Russia has neither the equipment nor production capacity to gather enough offensive strength to take the entire country. At this point Russia's best case scenario is a protracted stalemate.

For the US and NATO, strategically we've already won the war beyond our wildest expectations when this began. With the support we've given, we've already gotten our hands on some of the best and latest Russian equipment. Russia's offensive military threat has been destroyed for at least a decade. Countries that had been trying not to anger Russia now feel the freedom and need to join NATO. In other words the threat in the short and medium term posed by Russia has been neutralized, Russia has been exposed as militarily incompetent and all with a minor investment in material without losing NATO troops.

If China decides to arm Russia that may give them some more capability but I find that unlikely as Russia has been unable to show enough military competence to make it worth the cost for China. Almost certainly Chinese equipment would also fall into NATO hands. China's relations with the west would be weakened and they would likely face an economic backlash that could hurt their already precarious situation as a source for inexpensive manufacturing. That source of inexpensive manufacturing is the basis for China's current economic strength and they are not going to put that in danger without a really, really good benefit to themselves. A benefit I don't currently see in the Ukraine conflict.