T. Charley - great advice for everyone.
Our DEFCON has always been based on nuclear threats, but there are a lot of other non-nuclear threats to USA and West, such as cyber threats to infrastructure. My greater concern is for the vulnerability of the larger USA cyber infrastructure: communications, banking, Internet, stock market, fuel centers, government, medical. WWII fighting did not have USA/NATO/West with such global cyber infrastructure connectivity that could be exploited by belligerents, during war time. Saboteurs largely had to be in-person threats that could be watched for, idenitified, and hopefully stopped. The global cyber infrastructure makes potential saboteurs much more invisible, not in person, and much more of a global threat.
The disaster in 2020 of SolarWinds being hacked and widespread hacking of USA Government sites demonstrates the magnitude of that threat. There is no doubt: that was a direct warning from Russia to USA.
en.wikipedia.org
My concern is that after Russia captures Kyiv and defeats the Ukraine government, if USA sanctions remain, if there will be elements in the Russia government that plan to act in response to what they call USA's "economic war" by cyber insfrastructure attacks.
I would way say, unlike concerns by others, that the USA electrical grid may not be as big of a threat, due to cyber attack alone, because of the air gap between the front office networked facilities and the separate industrial control systems (ICS) that are used in each power plant for overall control. I believe this division is a strength (possibly not intentional) of USA infrastructure cyber defense, but there is a lot of other massive vulnerability.