Would the Americas be obliged to join NATO self-defence (and vice-versa)?

In both NATO¹ and the OAS², a military attack on one member state is seen as a military attack on all member states.³

Considering the USA is a member of both NATO and OAS, this provides a bridge between the two organisations. Theoretically, then, an attack on a member state of either organisation would lead to all members of both organisations helping out.

So let’s say Germany was invaded. As Germany is a NATO member, and an attack on a NATO state is an attack on all member states, all other NATO member states would have to help. Thus an attack on Germany would be considered an attack on the USA.

Now, as USA is now ‘under attack’, and an attack on one OAS state is an attack on all member states, all other OAS members would have to offer assistance. An attack on the USA would be considered an attack on, for example, Argentina.

Ergo, Argentina would have to help the USA help Germany. An OAS nation would have to help a NATO nation. More importantly, the implication is that OAS nations would be dragged into a NATO conflict (and vice-versa).

Whether this would happen in reality is a different matter altogether. The treaties³ may only account for one degree of separation between member states rather than frog-leaping the two degrees of separation via the USA between two organisations. The only way to truly know would be for a NATO or OAS country to be invaded but I’d rather stay curious then see more conflicts break out.

1 North Atlantic Treaty Organisation

2 Organisation of American States

3 For NATO, this is under Collective Defence – Article 5. For OAS, this is under Inter-American Treaty of Reciprocal Assistance Article 3.1 (commonly known as the ‘Rio Treaty’).