IIRC CalBear once said that a successful Eagle Claw was basically ASB, so let's say Carter closes the embassy in late 1978 instead.
You've still got an incompetent, floundering president who is losing over 30% of Democrats and whose approval in July '79 is at 28%, plus the crap economy. What this means is that Ted Kennedy, if he launches a properly run campaign, could potentially successfully primary Carter, or come close enough to force Carter's abdication like his brother did LBJ 12 years earlier. If Kennedy unseats Carter, the liberals come back but the moderates get sent straight into Reagan's arms.