India, Russia, and China will still trade with Iran as much as they want to. China imports a higher percentage of oil from Iran than the US does from Saudi Arabia. India and Russia are busy increasing trade with Iran as well. And all of those transactions are carried out in rials, rubles, or yuan, not dollars or euros. Then you have South America, specifically Venezuela and Brazil, which no longer gives a hoot about US or EU hegemony in the world.
Shaffir to Herzog: Opposition failed to show leadership in political battles against PM (Haaretz)
from the article: EU agrees on oil embargo over Iran nuclear program