Iran wasn't our friend. The Shah was our friend. Clearly much of Iran didn't appreciate our meddling in that country, and that's why the Shah was chased out of there. Iran could have been our friend had we not crushed their fledgling democracy because of oil and had we not propped up the despotic Shah.

And while my synopsis of our foreign relations looks simplistic because it didn't take very many words to communicate it, it's not at all simplistic when one examines the particulars of how we go about it.

But it's still entirely about empire and not wanting to allow the existence of any other superpowers that could challenge our hegemony.