Because much of the cooperation between Iran and North Korea is shrouded in mystery, their relationship is ripe for exploitation, particularly by those who are eager to find a hammer to destroy the impending nuclear agreement with Iran. But if this is the only implement that critics can find to inflict damage, they're scraping the bottom of their toolbox of destruction.
What the Venezuela sanctions made clear is that President Obama's opening to Cuba represented exactly zero change in Washington's overall strategy toward the region: The intention of expanding commercial and diplomatic relations with Cuba was mainly to pursue a more effective strategy of undermining the Cuban government -- and all the left governments in the region.
As the price of oil crumbles, declining over 25% since June, the consequences on the Russian economy have been drastic. What American and European sanctions (brought as a result of the annexation of Crimea) and the Ukraine crisis failed to do to the Russian economy, the declining price of oil has done.