will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.
the issue is the exact wording is
https://www.nato.int/en/what-we-do/introduction-to-nato/collective-defence-and-article-5
“such action as it deems necessary”
assistance can mean many things, and can be very very minimal… eg purposefully ineffective sanctions would satisfy “will assist”