[mikeash]

What stops the Saudis from doing the same? Given current events, it looks like they are.

[tomohawk]

Their vastly smaller population. Also, unlike Iran, they have not been talking about doing things like wiping out Isreal, etc.

Once Iran consolidates power in the areas they're operating in (Yemen, Iraq, Syria), the next obvious target is Saudi Arabia.

[mikeash]

Back to your 1939 analogy, that sounds just like reasons for allying with the Nazis.