I will respectfully disagree. There is a reason that US and Russian forces never engaged each other directly (not via proxy) in the Cold War - the threat of nuclear escalation.
That said, if a land based power and a sea based power engage in a very limited (ie tactical) nuclear exchange, the sea based power would be at a disadvantage: land forces are more spread out and can be replaced significantly faster vs naval forces (and infrastructure) that are very high value targets that take years to replace.
Yes but I am not talking about U.S. forces directly engaging Russian forces, I am talking about sanctions and proxy fighting (supply the Ukrainians). That said, the Russians need to be fearful of challenging the United States in the same way that many in the U.S. are fearful of Russia.
Many seem to have the view that Putin is crazy but I don't think so at all. I think he is an ultra-patriotic Russian nationalist who sees it as his sacred duty to protect Russia against the decadence of the West (as he sees it) and rebuild the Russian empire. Ukraine is a major keystone in that. The other former Soviet bloc states are nice to have too, but Ukraine is the major prize. It accounted for I believe about 70% of Soviet agricultural production during the Cold War. It has the most fertile agricultural soil in the world.. It is a land route through which to invade Russia. It has important natural resources and it provides access to the Black Sea via the warm water port at Sevastopol.
This is just my opinion if course, but saying Putin is crazy I think is applying a Western mindset to what is not a Western mindset. The Russian mindset is alien in many ways to a Westerner. For two reasons:
1) Communism and the collectivist brainwashing that occurred along with the lack of knowledge, upbringing, or understanding of human rights as we know them
2) WWII. Russia still hasn't psychologically gotten over what happened to them in WW2 by Germany. They lost anywhere from 20 - 40 million people and the level of brutality exhibited by the Germans was extreme (shooting babies, burning people alive, etc...).
And then unfortunately many Russians do the exact same thing many Westerners do, which is to apply THEIR mindset to the West, so they think the West thinks and reasons like them. So to a Westerner, the Russians and Putin are just bullies and liars and thugs. They know there is no threat of the West invading Russia or anything like that. From the Russian mindset though, it is different. They see a majorly important piece of land that directly borders Russia possibly joining NATO. They see the West more and more encroaching the sacred Russian homeland and Russia becoming more and more vulnerable to potential invasion should the West ever fall prey to a Hitler again. IRONICALLY, there is some truth to this too I think, because there are those who say it would be a bad idea right now to let Germany build up a fully offensive capable military, if it so desired.
The thing is though, the Russians themselves ARE bullies and seek to expand their territory in the name of communism and glory. So it's a weird combination of protect the sacred Russian homeland/expand communism around the whole planet, although maybe not so much the communism aspect now but Russia is not a land of free enterprise either.
I think Putin has just made a calculated decision that now is the time to try and take Ukraine. Western Europe is highly dependent on Russian energy, the U.S. public is war weary, the U.S. leadership are idiots, and Russia he believes has enough military capability to pull it off.