https://www.washingtonexaminer.com/opinion/dont-worry-the-us-would-win-a-nuclear-war-with-russia

Putin knows this. All hiis bluster does not change the calculus or
the facts - the US has much better, more modern and much more precise
nuclear weapons than Russia.

Look at the performance of the Russian army, air force and navy in a
David and Goliath war with Ukraine? That ineptitude would also plague
the Russian space and nuclear forces. They simply are not up to it.

The attack subs would not be able to track or even find the Ohios and
Virginia and Seawolf classes, but the US attack subs would easily find
the Russian boomers. Probably sink them in their ports.

The Russians would not get their bombers anywhere near the US and the
Russian surface fleet wouldn't last more than half a day or less. The
US stealth bombers, even the BUFFs, would have a field day over
Russia, Byelorussia and probably Kazakhstan.

So, nuclear war is thinkable and winnable. A lot of damage would be
done to the US, entire cities gone forever, irradiated tracts of once
fertile land etc etc. But the US would rebuild, Russia would not. And
if China was not involved, then of course China would take over the
Russian remnants, unless of course the US took out China as well,
which would be a sideshow to the main show.

So far, Biden is at DEFCON 3. See here:

https://www.defconlevel.com/current-level.php

It's been that way for a while and hasn't changed. The US isn't
worried about Putin pushing any buttons. Putin knows the score.

And I haven't even talked about the US's neutron bombs, dialable yield
gravity bombs and nuclear tactical cruise missiles...