1. At a time when ISIS in Iraq has suffered major defeats, can Iran claim to deliver a solution? Especially since the Iran-backed Hashid al-Sha’bi militias have apparently played a major role in this regard?
Let’s be clear. Hashid al-Sha’bi and Iran’s Revolutionary Guards (IRGC), as its true commander, have not played a major role in the fight against ISIS. Iran-backed forces have taken advantage of US airpower and only filled the void of ISIS on the ground after their defeats. This means a large portion of Sunni areas in Iraq is under their control. US inaction in the face of Iran in the past 16 years opened windows to most opportunities for this regime.
The most important element threatening Iraq, and especially peace and tranquility in the entire region, is the presence of IRGC and Shiite militias to replace the void of ISIS. This is a major challenge facing the US today. The war against ISIS will not render peace and security in the Middle East without the complete eviction of Iran’s IRGC and militias from Iraq and Syria.
  1. There are voices, especially in the US, heard claiming blacklisting the IRGC will do against international efforts, and especially US forces in defeating ISIS. Will designating the IRGC as a terrorist entity decrease regional crises?
First I must ask does the IRGC truly seek the complete annihilation of ISIS. This is an illusion promoted by Iran and its allies in the West to enjoy the pensions of fighting ISIS. It is true that Iran and ISIS are facing off in some areas. However, Tehran and its militias are seeking to replace the Sunni ISIS with their Shiite flag. Such a mentality and objective itself religiously and socially strengthens the very philosophy behind ISIS’ existence.
Look how it all started. The crimes committed by Syrian dictator Bashar Assad and former Iraqi prime minister Nouri al-Maliki provided the social grounds for ISIS’ birth by releasing al-Qaeda prisoners or allowing their escape. ISIS has also enjoyed IRGC logistical, substantial and arms support. Many senior ISIS members lived in Iran for years and Tehran dispatched them to Iraq and Syria with the aim of launching a sectarian war.
https://www.forbes.com/sites/heshmatalavi/2017/06/23/understanding-the-threats-of-iran/#5ecf8c3f4794