None of these are valid concepts. The reality is that Russia is in a conflict with Ukraine. Activating alliances brings those other countries into the conflict, which is exactly how WW1 became a world war. The USA has nothing to do with this conflict (except the entire casus belli, but let's go with your position). If the US was neutral, Ukraine would lose and Russia and Ukraine would negotiate a security arrangement to prevent further conflict.

But the US has supplied Ukraine with the equivalent of the entire Russian military budget 3 years in a row. Ukraine keeps fighting exclusively because of US support. But, that has been limited to the borders of Ukraine, which creates sufficient ambiguity that only allows Russia to escalate rhetoric. As soon as the US's involvement creates the conditions for strikes on Russian territory, now the USA is a participant in attacks against Russia, making it an escalatory move on the USA's part. The USA could just stay out of it and this whole thing will resolve itself with far fewer deaths and far less destruction.