Subject: Re: NATO
If Iran attacks America, does that mean NATO is null and void if the Europeans don't defend America?

Hardly, says AI:

The Mandate of Article 1

This is the "good faith" clause of the treaty. It explicitly requires members to:

"...refrain in their international relations from the threat or use of force in any manner inconsistent with the purposes of the United Nations."

If a member state violates Article 1 by launching an unprovoked strike, they have breached the treaty itself. It is logically and legally difficult to demand the benefits of a treaty (Article 5) while you are actively violating its core premise (Article 1).