Neither part of that is true. The US and the entire world economy will suffer immeasurably if there's all out war. The US will be seen as even more ineffectual internationally than it already is after Afghanistan, emboldening Chinese aggression in Taiwan and elsewhere.
Russia - lets be clear, the country that is threatening an all out invasion of a Sovereign nation it's already attacked and occupied; has the possibility of gaining territory, blocking NATO expansion, threatening it's former Warsaw Pact partners into favourable deals, gaining control over Ukraine's enormous agricultural resources, etc etc.
The Russian military was in the Crimea two centuries ago, and has been there ever since. The new aspect in the past decade is western calls for them to be removed.
The revival of Ukrainian nationalism in the modern era was actually a major project of Lenin's. The west is picking up and working on Lenin's own project, although in a slightly different form.
The Cuban government has for decades asked the US to remove its military presence from Cuba, including the detention center where it kidnaps people from random countries (again, against protest from those countries) and tortures them. Perhaps white upper middle class western liberals can rally to the Cubans cause.
Russia - lets be clear, the country that is threatening an all out invasion of a Sovereign nation it's already attacked and occupied; has the possibility of gaining territory, blocking NATO expansion, threatening it's former Warsaw Pact partners into favourable deals, gaining control over Ukraine's enormous agricultural resources, etc etc.