It was presumably these proxies for the Islamic Republic that Hezbollah leader Hassan Nasrallah was referring to on Wednesday when he said in a televised speech that Iran and its allies have “many strong cards” to play in their mutual conflict with the West. Nasrallah acknowledged that the public response to Monday’s IRGC terrorist designation had so far been limited to verbal condemnation, but he intimated that this could change at any moment. “There will be an appropriate response for sure,” he said cryptically.

In roughly 10 years following its founding in 1982, more than 300 deaths of American personnel were attributed to the terrorist group, acting on behalf of its handlers in Tehran. This led to Hezbollah being designated as a terrorist organization long ahead of the IRGC. Much more recently, some American allies in Europe and the Persian Gulf region have followed suit with their own Hezbollah terror designations, and critics of the Iranian regime are hopeful that those same world powers will see fit to extend the designation to what is effectively its Iranian parent organization.

In the days since the announcement, the American effort to blacklist the IRGC has met with considerable debate, although most of this has focused on the practicality of the sanctions measures and not on the justification for accusations against the hardline paramilitary. In explaining the announcement, Secretary of State Mike Pompeo made reference to recently revised casualty figures from the Pentagon, which suggested that the IRGC was linked to more than 600 deaths of US service members in Iraq between 2003 and 2011.

These figures also underscored the danger posed to US nationals and to Western interests in that country, where 5,200 American soldiers remain stationed after having been deployed at the request of the Iraqi government, to aid in the fight against Sunni militants of the Islamic State group. With ISIL now almost entirely defeated, Iraq and Syria have both become theaters of competition between American and Iranian influence, and local IRGC-linked militants are being urged to help push the US out of the region.

The US blacklist of those militants’ handlers now threatens to have an impact on the political conflict between Iran and the US. This was the implication, for instance, of reports that quoted Iraqi Prime Minister Adel Abdul Mahdi as saying the move “could have negative repercussions on Iraq and the region.” Mahdi told the press that the Iraqi government had tried to stop the terror designation, but it was not immediately clear why. Neither was it immediately clear what negative consequences he and other Iraqi officials were envisioning amidst rumors of the American announcement.

One explanation for Mahdi’s comments is that he was reacting to pressure from Iran-backed figures within the political establishment. The years-long entrenchment of Shiite militant groups has led to a number of them fielding candidates for high office and acquiring a growing share of power in the political establishment. At the same time, the paramilitary groups remain operational in parallel with the regular Iranian military, and officials like Mahdi presumably remain fearful of the damage they could do if provoked.

Certainly, the US terror designation for the backers of these militants is a potential source of provocation. But the potential consequences of that provocation can also credibly be characterized as a reason why it is imperative for the US to curtail IRGC influence before it grows even more expansive. Meanwhile, threats from Hezbollah and other IRGC affiliates underscore the danger that unchecked influence could pose to Western personnel and interests throughout the region, not just in areas of recent or ongoing conflict such as Iraq and Syria.