Would NATO help a member country in war with a nuclear power?

Why would it be better to preserve an enslaved humanity than to call the bluff and fight back? We need to be prepared for global nuclear war if we want to defend ourselves, otherwise we are just posers and might as well give up now. Deterrent doesn't mean anything if you wont actually use it if necessary

Yes.

One of the points of NATO was (and still is, especially today) to protect European countries against the USSR with the so-called American "nuclear umbrella". So to use the American nuclear deterrent to protect against Russia, also a nuclear power.

Would NATO helping a member country conflict with preserving humanity? Theoretically, and as we are seeing now, is that the aggressor may not be preserving humanity nor acting humanely.

That's the primary reason for its existence, but until it actually happens there's no way to know for sure.

> Wouldn't preserving humanity be more important?

The observed behavior of world leaders over the decades suggests otherwise. People are often quite willing to risk their lives in collective endeavors, like wars, which probably made sense in evolutionary terms. Evolution though can't effectively adapt to the existence of species ending weapons.

Assuming you're talking about Russia, I'm counting on it. It's the whole reason NATO exists. Otherwise Russia, or anyone else with nuclear weapons could just eat up their non-nuclear neighbors until there were no non-nuclear states left.

Since NATO calls for mutual support, would an aggressor start a war against multiple nuclear powers? The hope is "no".